Answer:
1.00 mole of He have [tex]6,02x10^{23}[/tex] atoms.
Explanation:
To solve this exercise it is important to know the definition of Avogadro's number
Avogadro's number is the proportional factor that relates the molar mass of a substance to the number of elementary units (atoms, molecules, particles, ions, electrons) that constitute it and its magnitude is equal to 6.022 140 857 × 10²³
One mole of helium we have [tex]6,02x10^{23}[/tex] atoms.
One mole of helium (He) contains 6.02 × 10^23 atoms, as this is Avogadro's number, which defines the number of entities per mole of a substance.
Explanation:The student is asking how many atoms are in 1.00 moles of helium (He). To answer this question, we need to use Avogadro's number, which is 6.02 × 1023 atoms/mole. Since one mole of any substance contains Avogadro's number of atoms, molecules, or ions, we can easily calculate the number of atoms in one mole of helium.
Therefore, 1.00 mole of He contains 6.02 × 1023 atoms of He. This is a direct conversion using the definition of a mole.
I've got a balanced equation that is asking about and i have no idea where to start. I will attach the question below: 4A + 3B2 -> 2A2B3 If 12 moles of A are reacted with excess B2, how many moles of A2B3 will be produced?
Answer:
6 mol of A₂B₃ are produced
Explanation:
This is the reaction:
4A + 3B₂ → 2A₂B₃
4 moles of A react with 3 moles of B to produce 2 moles of A₂B₃.
Ratio is 4:2. Therefore:
4 moles of A will produce 2 moles of A₂B₃
12 moles of A, would produce (12 .2) / 4 = 6 moles
By applying the stoichiometric ratios from the balanced chemical equation 4A + 3B2 -> 2A₂B₃, it's determined that reacting 12 moles of A with excess B₂ will result in the production of 6 moles of A₂B₃.
To solve this, we look at the balanced chemical equation given: 4A + 3B₂ -> 2A₂B₃. This equation tells us that 4 moles of A react with 3 moles of B₂ to produce 2 moles of A₂B₃. Using this ratio, we can set up a proportion to find out how many moles of A₂B₃ will be produced when 12 moles of A are used. Since 4 moles of A yield 2 moles of A₂B₃, 12 moles of A will yield:
(12 moles A / 4 moles A) * 2 moles A₂B₃ = 3 * 2 moles A₂B₃ = 6 moles A₂B₃.
Therefore, reacting 12 moles of A with an excess of B₂ will produce 6 moles of A₂B₃.
Explain, in terms of particles, concentration, and reaction rate, what you expect to happen when liquid water is sealed in a flask on a warm day and reaches a state of equilibrium. H2O (l) H2O (g).
Answer:
Kinetic Energy is involved here
Explanation:
On a warm day, the temperature of H20(l) will be high and that will make the particles of water to possess more kinetic energy and particles tend to move faster. Due to the fast movement of the particles, some of the particles turns into gaseous form (vapour). This makes the volume (concentration) of the liquid water decrease while that of the vapour keeps increasing due to the temperature of the day, until the equilibrium point is reached. At the equilibrium point, the forward and the backward rates are equal and the concentration of liquid water and vapour is the same.
From the following enthalpy of reaction data and data in Appendix C, calculate ΔH∘f for CaC2(s): CaC2(s)+2H2O(l)→Ca(OH)2(s)+C2H2(g)ΔH∘=−127.2kJ
The standard enthalpy of formation of CaC2(s) can be calculated using the provided enthalpy of the reaction and the standard enthalpies of formation for the other substances participating in the reaction, which can be found in Appendix C.
Explanation:In order to calculate the enthalpy of formation (ΔH∘f) for CaC2(s) from the given enthalpy of reaction data, we will use the thermochemical equation and the data from the appendix. The given reaction, CaC2(s)+2H2O(l)→Ca(OH)2(s)+C2H2(g), has an enthalpy of -127.2kJ.
Using this we can rearrange the equation to find the enthalpy of formation of CaC2(s) i.e. ΔH∘f (CaC2(s)) = ΔH∘reaction + ΔH∘f (Ca(OH)2) + ΔH∘f (C2H2) - [ΔH∘f (CaC2) + 2×ΔH∘f (H2O)].
To find ΔH∘f for CaC2(s), we need the values of standard enthalpy of formation of the other substances participating in the reaction, which can be found in Appendix C.
Learn more about Enthalpy of Formation here:https://brainly.com/question/14563374
#SPJ12
A group of students were asked to identify three white powders. The students use the physical and chemical properties to identify the powders. They computed The density of each powder. They check to see if any dissolved in water. One of the powders did not dissolve in water and they thought it was corn starch. They knew that cornstarch felt slippery and reacted with iodine. The students put a few drops of iodine on each white powder. One powder turned black it was definitely cornstarch. Another powder, baking soda reacted with vinegar. It first and the test tube got hot. Which of these is an observed chemical property? A. Color of powders B. Density of powders C. Powder dissolved in water D. Powder reacts with vinegar? Please please please help me
Answer:D. Powder react with vinegar
Explanation: All the other choice is physical change. Choice A is a change of color but it doesn’t change the properties. Choice B is an example of physical change which is simply for measurements therefore doesn’t affect the properties. Choice C is also physical change because solubility and dissolve are type of physical change leaving us with the last choice which is choice D. Since the powder reacts with the vinegar it changes the property of the powder.
The reaction between the white powder and vinegar is a chemical property where the chemical bonds are involved in the change to produce new products.
What is chemical property?There are broadly two types of properties called physical properties and chemical properties. Physical properties involves the color, size, shape , phase, and phase transitions etc. Boiling point, melting point, solubility etc are physical properties.
Chemical properties include the changes in chemical bond between atoms such as breaking or formation or both for chemical bonds. The reaction between two compounds leads to breaking and making of chemical bonds and form new products.
Density, solubility, color etc are physical properties of the substance whereas its reactivity towards vinegar is a chemical property. Hence, option D is correct.
To find more on chemical properties, refer here:
https://brainly.com/question/1935242
#SPJ5
Refrigerators are usually kept at about 5°C, while room temperature is about 20°C. If you were to take an ""empty"" sealed 2-liter soda bottle at room temperature and place it in the fridge, would you expect it to contract to one-fourth its original volume?
1. Yes, because 5 is one-fourth of 20.
2. No, because there is no gas inside the bottle.
3. No, because Celsius is not an absolute temperature scale.
Answer: option 3. No, because Celsius is not an absolute temperature scale.
Explanation:
Answer:
3. No, because Celsius is not an absolute temperature scale.
Explanation:
Note that 20∘C=293K and 5∘C=278K . So the absolute temperature has not decreased by very much at all, certainly not by a factor of four. Therefore, the change in size of the plastic bottle would not be very noticeable.
What is a mole? and how to I convert grams to kilograms and all that?
Answer:
A mole is equal to 6.022 × [tex]10^{23}[/tex] atoms/molecules.
Explanation:
A mole is a unit of measurement. Think of it as a unit of measurement just like a dozen of eggs is equal to 12 eggs, one mole is equal to 6.022 × [tex]10^{23}[/tex] atoms/molecules. This number, 6.022 × [tex]10^{23}[/tex], is known as Avogadro's number and you use it to convert from the number of moles to the number of atoms or molecules.
For example, if you want to convert 81 grams of water ([tex]H_{2}O[/tex]) to the number of atoms, you will need to use Avogadro's number. First, you have to find the molar mass of the water. To do this, you look at the periodic table and find the mass of hydrogen and oxygen because those are the elements that make up water. The subscript of the element tells you how many atoms of that particular element you have. So water has 2 hydrogen atoms and 1 oxygen atom. The molar mass tells you how many grams of a substance makes up 1 mole of that substance and it will vary by substance (no two different substances will have the exact same molar mass).
Molar Mass of Water: (2 × 1.008 g) + (1 × 15.999 g)= 18.015 grams
After we find the molar mass of the substance, we can use Avogadro's number to convert from grams to moles and then from moles to the number of atoms.
[tex]\frac{81 grams H_{2}O }{1} * \frac{1 mole H_{2}O }{18.015 grams H_{2}O } * \frac{6.022*10^{23} atoms}{1 mole H_{2}O } = 2.708*10^{24}[/tex] atoms of [tex]H_{2}O[/tex]
To convert grams to kilograms you need to know the conversion factor between them which is 1000 grams equals 1 kilogram. For example, if you are given 7,389 grams and you want to convert that to kilograms you do:
[tex]\frac{7389 grams}{1}[/tex] × [tex]\frac{1 kilogram}{1000 grams}[/tex] = 7.389 kilograms
I hope this helped clear things up a bit!
White vinegar is available as a 5% acetic acid solution and a 10% solution, by volume. How many millilitres of each solution must be added to make 100ml of a 7%solution?
Answer:
The answer to your question is 60 ml of solution 5% and 40 ml of solution 10 %
Explanation:
Data
acetic acid = 5% = concentration 1
acetic acid 2 = 10% = concentration 2
final solution = 7 % =
final volume = 100 ml
Process
1.- Write an equation of the process
x = volume of solution 5%
100 - x = volume of solution 10%
Final concentration x final volume = concentration 1 x volume 1 + concentration 2 x volume 2
0.07(100) = 0.05x + 0.10(100 - x)
2.- Solve for x
7 = 0.05x + 10 - 0.1x
7 - 10 = 0.05 - 0.1 x
- 3 = -0.05 x
x = -3/-0.05
x = 60 ml of solution 5%
3.- Calculate the volume of solution 10%
Volume of 10% = 100 - 60
Volume of 10% = 40 ml
Write a half-reaction for the oxidation of the manganese in MnCO3(s) to MnO2(s) in neutral groundwater where the carbonate-containing species in the product is HCO3–(aq). Add H2O and H+ to balance the H and O atoms in the equation. Do not add electrons; you may leave the half-reaction unbalanced with respect to charge.
Answer:MnCO3+2H2O----->MnO2+ HCO3-+2e-+3H+
Explanation:The equation to be balanced is
MnCO3 ------> MnO2+HCO3-
The oxidation number of Mn changes from +2 in MnCO3 to +4 in MnO2
Therefore two electrons must be added to the right as shown below:
MnCO3 -------> MnO2+ HCO3-+ 2e-Now,there is one negative charge HCO3- and 1 negative charge on the two electrons making a total of -3 charges on the right. There is zero charge on the left.
To balance the equation,add3H+on the right,to cancel out the charges.
MnCO3 --------> MnO2+HCO3-+2e-+3H+
Adding H2O to balance Hydrogen and Oxygen atoms:
MnCO3+2H2O ------->MnO2+HCO3-+2e-+3H+
The half reaction for the oxidation of Manganese has been [tex]\rm MnCO_3\;+\;2\;H_2O\;\rightarrow\;MnO_2\;+\;HCO_3^-\;+\;2e^-\;+\;3\;H^+[/tex]
Oxidation has been defined as the loss of electrons by an element. The half reaction has been the oxidation reaction in the redox reaction.
Half reaction of oxidationIn the reaction of Manganese carbonate to manganese dioxide, there has been change in the oxidation number of Mn from +2 to +4. The change in the oxidation state has been balanced with the addition of electrons.
The carbonate charge has been balanced in the reaction with the addition of hydrogen and water molecules.
The half reaction for the oxidation of Manganese has been [tex]\rm MnCO_3\;+\;2\;H_2O\;\rightarrow\;MnO_2\;+\;HCO_3^-\;+\;2e^-\;+\;3\;H^+[/tex]
Learn more about half reaction, here:
https://brainly.com/question/7485080
Draw the addition product formed when one equivalent of hcl reacts with the following diene.
Answer:
Major Product = 4-chloro-4-methylcyclohex-1-ene
Explanation:
Alkene are the class of organic compounds which contain one or more double bonds between two carbon atoms. Alkenes are considered most reactive among the unsaturated hydrocarbons and they undergo addition reactions due to high electron density around the double bonds.
In given question it is written that we are provided with one equivalent of HCl while, our compound contains two double bonds (diene) so in selected starting material the HCl will be added across (hydrohalogenation reaction) the substituted double bond because it will give a more stable carbocation (tertiary carbocation) during the reaction course. Hence, as shown in reaction scheme 4-chloro-4-methylcyclohex-1-ene will be the major product.
A balloon is filled to a volume of 1.50 L with 3.00 mol of gas at 25 C. with pressure and temperature held constant, what will be the volume of 1.40 moles of gas are added?
Answer:
3.2L
Explanation:
PV=nRT
since pressure and temperature are held constant we have V=nR
R is a constant also,
Thus; [tex]\frac{v1}{n1}=\frac{v2}{n2}[/tex]
v1=1.5L , n1=3mol, n2=1.4mol
[tex]\frac{1.5}{3}=\frac{v2}{1.4}[/tex]
v2=[tex]\frac{1.5}{3}*1.4[/tex]
v2=3.2L
Consider the KF molecule, which has an ionic bond. The bond length is 2.17 x 1010 m (a) Calculate the energy required to dissociate the KF molecule into the ions K* and F |(b) The energy required to dissociate KF into neutral atoms is 498 kJ/mol. Given that the first ionization energy for K is 418 kJ/mol, calculate the electron affinity (in kJ/mol) for F. Show your work for all calculations 2. (a) +6.40 x 10 kJ mol1 or +1.06 x 1018 J (b) +276 kJ mol
Answer:
a) +640 kJ/mol or +1.06x10⁻¹⁸ J
b) +276 kJ/mol
Explanation:
To dissociate the molecule, the bond must be broken, thus, it's necessary energy equal to the energy of the bond, which can be calculated by:
E = (Q1*Q2)/(4*π*ε*r)
Where Q is the charge of the ions, ε is a constant (8.854x10⁻¹²C²J ⁻¹ m⁻¹), and r is the bond length. Each one of the ions has a charge equal to 1. The elementary charge is 1.602x10⁻¹⁹C, which will be the charge of them.
1 mol has 6.022x10²³ molecules (Avogadros' number), so the energy of 1 mol is the energy of 1 molecule multiplied by it:
E = 6.022x10²³ *(1.602x10⁻¹⁹)²/(4π*8.854x10⁻¹²*2.17x10⁻¹⁰)
E = +640113 J/mol
E = +640 kJ/mol
Or at 1 molecule: E =640/6.022x10²³ = +1.06x10⁻²¹ kJ = +1.06x10⁻¹⁸ J
b) The energy variation to dissociate the molecule at its neutral atoms is the energy of dissociation less the difference of the ionization energy of K and the electron affinity of F (EA):
498 = 640 - (418 - EA)
640 -418 + EA = 498
222 + EA = 498
EA = +276 kJ/mol
The energy required to dissociate the KF molecule into K+ and F- ions is -1.76 x [tex]10^5 kJ/mol.[/tex]n affinity of F is -80 kJ/mol.
Explanation:To calculate the energy required to dissociate the KF molecule into the ions K+ and F-, we need to consider the bond length and the charges of the ions. The equation to calculate the energy is given by:
E = k * (q1 * q2) / r
where E is the energy, k is the Coulomb constant[tex](9 x 10^9 N m^2/C^2),[/tex]rges of the ions (+1 for K and -1 for F), and r is the bond length.
Using the given bond length, we have:
E = [tex](9 x 10^9 N m^2/C^2)[/tex](2.17 x[tex]10^-10 m)[/tex]
E = -[tex]1.06 x 10^18 J[/tex]
To convert this to kJ/mol, we divide by Avogadro's number:
E = -[tex]1.06 x 10^18 J / 6.022 x 10^23 mol-1[/tex]
E ≈ -[tex]1.76 x 10^5 kJ/mol[/tex]
To calculate the electron affinity (EA) for F, we can use the equation:
EA = Ionization Energy(K) - Dissociation Energy(KF) = 418 kJ/mol - 498 kJ/mol = -80 kJ/mol
In water, hydrogen bonding occurs between the hydrogen atom in one molecule and __________.
Question options:
A) an oxygen atom in the same molecule.
B) an oxygen atom in a different molecule.
C) a hydrogen atom in the same molecule.
D) a hydrogen atom in a different molecule.
E) None of the above
Answer: B) an oxygen atom in a different molecule.
Explanation:
Hydrogen bonding (H-bonding) is an inter molecular force having partial ionic-covalent character.
H-bonding takes place between a hydrogen atom attached with an electronegative atom such as O, N and F and an electronegative atom such as O,N and F. They are strong forces.
Example: [tex]H_2O[/tex] has hydrogen bonding between hydrogen of one molecule with oxygen atom bonded to hydrogen of different molecule.
Thus the correct option is hydrogen bonding occurs between the hydrogen atom in one molecule and an oxygen atom in a different molecule.
In water, hydrogen bonding occurs between the hydrogen atom in one water molecule and the oxygen atom in a different water molecule. This is due to the large dipole moment caused by oxygen being more electronegative than hydrogen.
Explanation:In a water molecule, hydrogen bonding occurs between the hydrogen atom of one molecule and an oxygen atom in a different molecule. Water molecules have a bent shape, with two hydrogen atoms and one oxygen atom. Because oxygen is more electronegative, the shared electrons between hydrogen and oxygen tend to stay closer to the oxygen atom, causing a dipole moment.
This dipole moment results in a partially positive charge on the hydrogen atoms and a partially negative charge on the oxygen atom. Hence, the hydrogen atoms from one water molecule are attracted to the oxygen atoms of another water molecule, forming hydrogen bonds.
Learn more about Hydrogen Bonding here:https://brainly.com/question/30885458
#SPJ3
What is the percent composition of copper in copper (II) hydroxide (Cu(OH)2 )? Question 7 options: a) 65.13 % Cu b) 32.80 % Cu c) 97.57 % Cu d) 2.07 % Cu
Answer:
The answer to your question is letter a. 65.13%
Explanation:
Percent composition of Copper in Cu(OH)₂
Process
1.- Calculate the molecular weight of Copper hydroxide
Cu(OH)₂ = 64 + (16 x 2) + (2 x 1)
= 64 + 32 + 2
= 98 g
2.- Solve the problem using proportions
98 g of Cu(OH)₂ --------------- 100 %
64 g of Cu ---------------- x
x = (64 x 100) / 98
x = 6400 / 98
x = 65.2 %
Final answer:
The percent composition of copper in copper (II) hydroxide (Cu(OH)2) is calculated using the molar masses of its elements. The molar mass of Cu(OH)2 is 97.57 g/mol, and the molar mass of copper (Cu) is 63.546 g/mol. The correct answer is 65.13% Cu.
Explanation:
To calculate the percent composition of copper in copper (II) hydroxide (Cu(OH)2), we need to calculate the molar mass of this compound first. The molar mass of Cu(OH)2 is 97.57 g/mol. Using the average atomic mass of copper (63.546 g/mol), we can determine the mass percentage of copper in the compound.
The molar mass of Cu(OH)2 is the sum of the molar masses of one copper atom (63.546 g/mol), two oxygen atoms (2 × 16.00 g/mol), and two hydrogen atoms (2 × 1.01 g/mol):
Molar mass of Cu(OH)2 = 63.546 g/mol (Cu) + 32.00 g/mol (O) + 2.02 g/mol (H) = 97.57 g/mol
Therefore, the percent composition of copper in Cu(OH)2 can be calculated as follows:
% Cu = (molar mass of Cu / molar mass of Cu(OH)2) × 100
% Cu = (63.546 g/mol / 97.57 g/mol) × 100 ≈ 65.13%
Hence, the correct answer is 65.13 % Cu.
Ice cream is made by freezing a liquid mixture that, as a first approximation, can be considered a solution of sucrose (C12H22O11) in water. Estimate the temperature at which the first ice crystals begin to appear in a mix
Answer:
Hi.
The temperature is approximately zero degrees (0°C)
Explanation:
It is important to keep in mind that in the production of ice cream the decrease in the freezing point of the water present in the mixture is called the antifreeze power of the mixture. In ice cream, the freezing point decrease will be caused by each substance that is dissolved in the mixture: lactose, salts, sugars and any other substance. Each of these substances will contribute to the decrease in the freezing point of the mixture. The phase diagram attached in the file shows the sugar solutions in water. When a solution cools (point A), there comes a time when the freezing curve is reached (point B). At that moment ice begins to appear. As shown in the diagram this temperature is approximately zero degrees (0 ° C).
The body’s pH is tightly regulated because specific enzymes function best within a narrow pH range. What is the approximate pH of a 1.2 × 10–5 M aqueous solution of NaOH?
Answer:
The answer to your question is pH = 9.08
Explanation:
Data
pH = ?
Concentration = 1.2 x 10⁻⁵ M
Process
1.- Calculate the pOH of the solution
Formula
pOH = -log[OH⁻]
pOH = -log[1.2 x 10⁻⁵]
pOH = 4.92
2.- Calculate the pH
Formula
pH = 14 - pOH
Substitution
pH = 14 - 4.92
Result
pH = 9.08
Rank these rock-forming minerals from most abundant to least abundant: (a) silicates, (b) carbonates, (c) sulfates, (d) oxides.
Answer:
Thus the correct order would be a, b,d and then c
Explanation:
Rank of rock-forming minerals from most abundant to least abundant
1. Silicates
2. Carbonates
3. Oxides
4. Sulfates
Thus the correct order would be a, b,d and then c
Sketch and explain the model for an atom, including electron shells and how the number of electrons in shells influence the loaning and transfer of electrons between atoms.
Answer:
The sketch and explanation is attached below.
Explanation:
Matter consists of atom, which is the smallest particle of an elements. Atoms consists of three parts; The protons which are positively charged, the neutrons which are neutral and the electrons which are negatively charged. both the proton and neutron make up the nucleus while the electron orbit outside of the nucleus.
Protons ; are positively charged which form the basis of the atoms. the symbol for protons is Z and the number of protons which make up an atom is also known as the atomic number which is a unique property of an element, no two elements must have the same atomic number.
Neutrons ; are neutral in an atom as such they do not have a charge and it is indicated by the letter N. the number of protons is the difference between the mass number and the atomic number of the proton number.
Electrons ; are negatively charged and they orbit outside of the nucleus of an atom. The mass of a proton is 1840 times greater than the mass of an electron.
Various scientist have given their own explanation of the model of an atom, people like Ernest rutherford, Neil bohr, John Dalton, JJ Thompson et al came up with different postulation of the atomic model. Neil bohr for example said about electrons they they do not only have energy, but they have a particular energy which are confined into energy levels that is the energy of the electrons were quantised. John dalton -the English scientist also came about his atomic theory ; each element has its own unique type of atom, atoms of each individual element have the same atomic weight, when atoms combine, they do so in fixed ratios. although most of dalton's theory have been modified.
An electron shell on the other hand comprises of the outer part of an atom i.e outside the nucleus. shells have sub-shells or sublevels. there are K-L-M shells. sodium (Na) for example has an atomic number of 11 and an electronic configuration of 2)8)1 - this implies that it has 3-shells -k-L-M and the last electron in its shells which is 1 is known as the valence electrons or the outermost electron. it is the number of electron at the outermost shell that takes part in the donating and accepting of electron.
Calcium(Ca) for example has an atomic number of 20, electronic configuration 2)8)8)2, K-L-M-N, it has four shells. the outermost electron (2) is the valence electron and it is the electron which determines the group of an element. this explains why sodium (Na) is a group 1 element and calcium (Ca) is a group 2 elements.
The valence electrons is the only electron that takes part in sharing during bonding. for example Sodium chloride(Nacl) - sodium has 1 electron at the outermost shell and chlorine has 7 electron in its outermost shell, hence its needs 1 more electron to attain the octet state , this 1 electron will be donated by Na to become a cation as such sodium becomes the reducing agent and chlorine is the oxidizing agent as it accept electron to become a anion. The essence of bonding or transfer or sharing of electrons is for atoms of element to either attain the octet or duplet state.
The atom model features a nucleus, electrons in shells, and valence electrons influencing bonding. Outer shell electron interactions drive covalent and ionic bonding, crucial in chemical reactivity.
The atom model is based on the understanding that atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in orbitals. The electrons are organized into electron shells, each with a specific energy level. The innermost shell is filled first before moving to the next, and the outermost shell determines the atom's chemical properties.
Electron shells are designated by principal quantum numbers (n), and each shell can accommodate a specific number of electrons. The first shell (n=1) can hold up to 2 electrons, the second (n=2) can hold up to 8, and so on. Electrons in the outermost shell are called valence electrons, and these play a crucial role in chemical bonding.
The number of electrons in the outermost shell influences an atom's reactivity. Atoms strive to achieve a full outer shell, following the octet rule. Some atoms achieve this by sharing electrons (covalent bonding), while others transfer electrons (ionic bonding). In covalent bonding, atoms share electrons to complete their outer shells, forming stable molecules. In ionic bonding, atoms transfer electrons, creating ions with full outer shells.
Understanding electron distribution in shells provides insight into an atom's behavior in chemical reactions, facilitating predictions about its bonding tendencies. This model, incorporating electron shells, enhances our comprehension of atomic structure and guides our understanding of chemical interactions.
For more such information on: atom model
https://brainly.com/question/28825274
#SPJ6
Calcium ions are removed from the sarcoplasm of the cardiac cell by the action of the sarcoplasmic reticulum (SR) Ca2+-ATPase pump and which other mechanism?
Answer:
Sodium-calcium exchanger on the sarcolemma
Explanation:
The sodium-calcium exchanger which is an antiporter membrane protein, removes calcium from cells. The energy of the electrochemical gradient of sodium is used by allowing it to flow down its gradient while moving across the plasma membrane
An air compressor takes atmospheric air (think about what pressure it is at) and pressures it up to 68 (psig). In the process, it warms up from 26 degC to 48 degC. If the original volume of air is 13 (m^3). What is the resulting volume (m^3) after the air is compressed and heated?
Answer:
5.19 m³
Explanation:
Data Given:
initial Pressure P1 = atmospheric pressure
Reported atmospheric pressure = 14.696 psi
Final pressures P2 = 68 psi
initial Temperature T1 = 26 °C
final Temperature T2 = 48 °C
initial Volume V1= 13 m³
final Volume V2 = ?
Solution:
Formula will be used
P1 V1 / T1 = P2 V2 / T2
To calculate volume rearrange the above formula
V2 = (P1 V1) T2 / T1 P2 . . . . . . . .(1)
put values in equation 1
V2 = (14.696 psi x 13 m³) 48 °C / 26 °C x 68 psi
V2 = (191.05 psi m³) 48 °C / 1768 °C psi
V2 = (9170.3 psi m³ °C / 1768 °C psi
V2 = 5.19 m³
So, final volume is 5.19 m³
The side chain (R group) of the amino acid serine is CH₂OH. The side chain of the amino acid leucine is CH₂CH(CH₃)₂. Where would you expect to find these amino acids in a globular protein in aqueous solution?A) Both serine and alanine would be in the interior and on the exterior of the globular protein. B) Alanine would be in the interior, and serine would be on the exterior of the globular protein. C) Serine would be in the interior, and alanine would be on the exterior of the globular protein. D) Both serine and alanine would be in the interior of the globular protein. E) Both serine and alanine would be on the exterior of the globular protein.
Answer: The correct choice is:
E) Both serine and leucine would be on the exterior of the globular protein.
Explanation:
The solubility and positioning of amino acids in a globular protein in aqueous solution are influenced by their side chains. Amino acids with hydrophilic (water-loving) side chains tend to be on the exterior of the protein where they can interact with water, while those with hydrophobic (water-fearing) side chains tend to be in the interior, away from water. In this case: Serine has a hydrophilic side chain (CH₂OH). Leucine has a hydrophobic side chain (CH₂CH(CH₃)₂). Therefore, you would expect serine to be on the exterior of the globular protein (interacting with water) and leucine to be in the interior (shielded from water). The correct choice is: E) Both serine and leucine would be on the exterior of the globular protein.
A student observes what happens when two different aqueous solutions are mixed in a test tube. Which of the following observations would be most indicative of a precipitation reaction?
a. Gas bubbles are produced.
b. A solid settles out.
c. There is a color change.
d. The test tube warms.
A precipitation reaction is indicated by the formation of a solid that settles out when two aqueous solutions are mixed. The correct answer is Option b.
Explanation:When two different aqueous solutions are mixed in a test tube, a precipitation reaction can be indicated by the formation of a solid that settles out. This occurs when two soluble compounds react to form an insoluble compound, which appears as a solid precipitate. Examples of precipitation reactions include mixing solutions of silver nitrate and sodium chloride to form a solid precipitate of silver chloride.
Learn more about Precipitation reactions here:
https://brainly.com/question/17074350
#SPJ3
Final answer:
The observation that most directly indicates a precipitation reaction when two aqueous solutions are mixed is b. A solid settles out, as this signifies the formation of a precipitate, which is a solid product of the reaction.
Explanation:
The question asks which observation is most indicative of a precipitation reaction when mixing two different aqueous solutions. Among the options given, the correct answer is b. A solid settles out. This is because a precipitation reaction involves the formation of a solid product, known as a precipitate, that separates from the clear solution. This precipitate can then typically be observed as sediment at the bottom of the test tube, or as a solid pellet if centrifugation is used. Options a, c, and d refer to other potential indicators of chemical reactions, such as gas formation, color change, and exothermic reactions, respectively, and while they may occur alongside precipitation, they are not as directly indicative of it.
An atom of a particular element is traveling at 1.00% of the speed of light. The de Broglie wavelength is found to be 3.31 × 10-3 pm. Which element is this? Prove it.
Answer:
The given atom is of Ca.
Explanation:
Given data:
Speed of atom = 1% of speed of light
De-broglie wavelength = 3.31×10⁻³ pm (3.31×10⁻³ / 10¹² = 3.31×10⁻¹⁵ m)
What is element = ?
Solution:
Formula:
m = h/λv
m = mass of particle
h = planks constant
v = speed of particle
λ = wavelength
Now we will put the values in formula.
m = h/λv
m = 6.63×10⁻³⁴kg. m².s⁻¹/3.31×10⁻¹⁵ m ×( 1/100)×3×10⁸ m/s
m = 6.63×10⁻³⁴kg. m².s⁻¹/ 0.099×10⁻⁷m²/s
m = 66.97×10⁻²⁷ Kg/atom
or
6.69×10⁻²⁶ Kg/atom
Now here we will use the Avogadro number.
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
Now in given problem,
6.69×10⁻²⁶ Kg/atom × 6.022 × 10²³ atoms/ mol × 1000 g/ 1kg
40.3×10⁻³×10³g/mol
40.3 g/mol
So the given atom is of Ca.
The movement of sounds, in the same manner, is called wavelength.
The correct element is Ca.
The data in the question is as follows:-
Speed of atom is 1% of the speed of light De-Broglie wavelength = [tex]3.31*10^{-3}\\\\\frac{(3.31*10^{-3}}{10^{12}}\\ = 3.31*10^{-15} m[/tex]
The formula we will used is [tex]m = \frac{h}{λv}[/tex]
The data is given is as follows:-
m = mass of the particle h = planks constant v = speed of particle λ = wavelength
Now we will put the values in the formula and solve the equation.
[tex]m = \frac{6.63*10^{-34}}{3.31*10^{-15} ( \frac{1}{100})*3*10^8}[/tex]
After solving the value of m is[tex]66.97*10^{-27}[/tex]
Now in the given problem, the solution is as follows:-
[tex]6.69*10^{-26}* 6.022 * 10^{23} * 1000[/tex]
After solving the equation the answer is 40.3
Hence, the 40.3 is the mass of calcium.
For more information, refer to the link:-
https://brainly.com/question/22810476
Copper is a trace element and nutrient in the diet of newborn babies, who require 80.0 μg per kg of body weight per day. Formula contains 0.48 μg/mL. How many mL of formula does a 6.60 lb baby require per day?
Answer:
498.95 ml of formula per day
Explanation:
Baby body requirement of copper per day = 80.0. μg per Kg
Copper content of formula = 0.48 μg/mL.
Mass of baby = 6.60 lb
1 lb = 0.4536 Kg
6.6 lb = 2.9937 Kg
Therefore baby needs
80μg/Kg/day × 2.9937 Kg = 239.5μg/day of formula
But formula contains 0.48 μg/mL that means baby needs
(239.5 μg/day)÷0.48 μg/mL = 498.95 ml of formula per day
498.95 ml/day
How many milliliters of calcium, with a density of 1.55 g/mL, are needed to produce 85.8 grams of calcium fluoride in the single replacement reaction below.
Answer:
We need 28.5 mL of Calcium solution
Explanation:
Step 1: Data given
Density = 1.55 g/mL
Mass of calcium fluoride (CaF2) = 85.8 grams
Molar mass of CaF2 = 78.07 g/mol
Step 2: The balanced equation
Ca + 2HF → CaF2 + H2
Step 3: Calculate moles CaF2
Moles CaF2 = mass CaF2 / molar mass CaF2
Moles CaF2 = 85.8 grams / 78.07 g/mol
Moles = 1.10 moles
Step 4: Calculate moles of Ca
For 1 mol mol CaF2 we need 1 mol Ca^2+
For 1.10 moles CaF2, we need 1.10 moles Ca^2+
Step 5: Calculate mass of Ca^2+
Mass Ca^2+ = moles Ca^2+ / molar mass Ca^2+
Mass Ca^2+ = 1.10 moles * 40.08 g/mol
Mass Ca^2+ = 44.1 grams
Step 6: Calculate volume of Ca^2+
Volume Calcium = mass calcium / density
Volume calcium = 44.1 grams / 1.55 g/mL
Volume calcium = 28.45 mL ≈ 28.5 mL
We need 28.5 mL of Calcium solution
Calculate the number of moles of solute present in each of the following solutions.
Part A 255mL of 1.70M HNO3(aq)
Part B 45.0mg of an aqueous solution that is 1.35m NaCl. Assume that for dilute aqueous solutions, the mass of the solvent is the mass of solution.
Part C 80.0g of an aqueous solution that is 1.50% sucrose (C12H22O11) by mass
Answer:
A. 0.433 moles of HNO₃
B. 6.07×10⁻⁵ moles of NaCl
C. 3.51×10⁻³ moles of sucrose
Explanation:
Part A.
Molarity . volume = moles
1.70 mol/L . 0.255L = 0.433 moles
Part B.
1.35 m of NaCl means, a molal concentration (m). Moles of solute in 1kg of solvent.
Let's convert 1 kg to mg for the rule of three
1 kg = 1×10⁶ mg
So in 1×10⁶ mg of solvent, we have 1.35 moles of solute (NaCl)
In 45 mg, we would have ( 45 . 1.35) / 1×10⁶ = 6.07×10⁻⁵ moles of NaCl
Part C. 1.50 % by mass means, 1.50 g of solute, in 100g of solution.
Let's make a rule of three:
In 100 g of solution we have 1.50 g of sucrose
In 80 g of solution, we would have (80 . 1.50) / 100 =1.2 g of sucrose.
Then, let's convert the mass in moles ( mass / molar mass)
1.2 g / 342 g/m = 3.51×10⁻³ moles
(A) 0.433 moles of HNO₃ in 255mL of 1.70M HNO3
(B) 6.07×10⁻⁵ moles of NaCl in 45.0mg of an aqueous solution that is 1.35m NaCl
(C) 3.51×10⁻³ moles of sucrose in an aqueous solution that is 1.50% sucrose (C12H22O11) by mass
(A) 255mL of 1.70M HNO3(aq)
Molarity × volume = moles
1.70 × 0.255L = 0.433 moles of HNO3
(B) 45.0mg of an aqueous solution that is 1.35m NaCl
1.35 m of NaCl means, a molal concentration (m). Moles of solute in 1kg of solvent.
In 45 mg, the number of moles is:
45 × 1.35 / 1×10⁶ = 6.07×10⁻⁵ moles of NaCl
(C) 80.0g of an aqueous solution that is 1.50% sucrose (C12H22O11) by mass
the solute is 1.50 % by mass, that is :
1.50 g of solute, in 100g of solution.
In 80 g of solution
80 × 1.50 / 100 =1.2 g of sucrose.
Now, convert the mass in moles
number of moles = given mass / molar mass
1.2 g / 342 g/m = 3.51×10⁻³ moles of sucrose
Learn more about moles conversion :
https://brainly.com/question/25921401
A package of aluminum foil is 68.6 yd long, 12 in. wide, and 0.00035 in. thick. If aluminum has a density of 2.70 g/cm3, what is the mass, in grams, of the foil?
Answer:
The answer to your question is mass = 455.6 grams
Explanation:
Data
Dimensions = 68.6 yd x 12 in x 0.00035 in
density = 2.70 g/cm³
mass = ?
Process
1.- Convert dimensions to cm
1 yd ---------------- 91.44 cm
68.6 yd ------------ x
x = (68.6 x 91.44) / 1
x = 6227 cm
1 in ----------------- 2.54 cm
12 in --------------- x
x = (12 x 2.54) / 1
x = 30.48 cm
1 in -------------- 2.54
0.00035 in ------------- x
x = (0.00035 x 2.54) / 1
x = 0.000889 cm
2.- Find the volume of the foil
V = 6227 x 30.48 x 0.000889
V = 168.73 cm³
3.- Find the mass of the foil
mass = density x volume
mass = 2.70 x 168.73
mass = 455.6 g
Final answer:
To calculate the mass of the aluminum foil, first convert all dimensions to centimeters, then calculate the volume (length × width × height), and finally multiply the volume by the density of aluminum (2.70 g/cm³). Therefore, the mass of the aluminum foil is approximately 457.94 grams
Explanation:
To find the mass of the aluminum foil given its dimensions and the density of aluminum, we need to follow these steps:
Convert all measurements to the same unit system, specifically to centimeters (cm) because the density is given in g/cm3.
Calculate the volume of the aluminum foil using the formula for the volume of a rectangular prism: Volume = length × width × height.
Multiply the volume by the density of aluminum to get the mass of the foil.
Step-by-Step Calculation
First, convert dimensions: 68.6 yd = 6265.44 cm (1 yd = 91.44 cm), 12 in = 30.48 cm (1 in = 2.54 cm), and 0.00035 in = 0.000889 cm.
Calculate the volume: Volume = 6265.44 cm × 30.48 cm × 0.000889 cm = 169.609 cm3.
Calculate the mass: Mass = volume × density = 169.609 cm3 × 2.70 g/cm3 = 457.94 grams.
The mass of the aluminum foil is approximately 457.94 grams.
Each molecule of testosterone contains 19 atoms of carbon (plus other atoms). The mass percent of carbon in testosterone is 79.12%. What is the molar mass of testosterone?A. 576.8 g/molB. 180.5 g/molC. 228.2 g/molD. 240.1 g/molE. 288.4 g/mol
Answer:
The answer to your question is letter E. 288.4 g/mol
Explanation:
Data
Number of carbons = 19
mass percent of carbon = 79.12
molar mass = ?
Process
1.- Calculate the molar mass of 19 atoms of carbon
Atomic mass of carbon = 12 g
Atomic mass of 19 atoms of carbon = 228 g
2.- Use proportions to calculate the mass of testosterone
228 g --------------- 79.12 %
x -------------- 100 %
x = (228 x 100) / 79.12
Simplify
x = 22800 / 79.12
Molar mass of testosterone = 288.2 g
how many moles of ions form when 51.0 g of calcium iodide is dissolved in water? how many ions form?
Answer : The number of moles of ions form are, [tex]3.14\times 10^{23}[/tex] and there are 3 ions formed.
Explanation :
First we have to calculate the moles of calcium iodide.
[tex]\text{Moles of }CaI_2=\frac{\text{ given mass of }CaI_2}{\text{ molar mass of }CaI_2}[/tex]
Molar mass of calcium iodide = 293.9 g/mol
Mass of calcium iodide = 51.0 g
[tex]\text{Moles of }CaI_2=\frac{51.0g}{293.9g/mole}=0.174moles[/tex]
Now we have to calculate the number of moles of ions.
As we know that when calcium iodide dissolved in water then it dissocites to give calcium ion and iodide ion.
The balanced chemical reaction will be:
[tex]CaI_2(aq)\rightarrow Ca^{2+}(aq)+2I^{-}(aq)[/tex]
From this we conclude that there are 3 ions formed.
As, 1 mole of calcium iodide dissociate to give [tex]3\times (6.022\times 10^{23})[/tex] number of ions
So, 0.174 mole of calcium iodide dissociate to give [tex]0.174\times 3\times (6.022\times 10^{23})=3.14\times 10^{23}[/tex] number of ions
Thus, the number of moles of ions form are, [tex]3.14\times 10^{23}[/tex]
binary compound created by reaction of an unknown element E and sulfur contains 27.52% E and 72.48% S by mass. If the formula of the compound is E4S10, calculate the atomic mass of E.
Answer : The atomic mass of E is, 30.4 g/mol
Explanation :
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of E = 27.52 g
Mass of S = 72.48 g
First we have to calculate the moles of sulfur.
Moles of S = [tex]\frac{\text{ given mass of S}}{\text{ molar mass of S}}= \frac{72.48g}{32g/mole}=2.265moles[/tex]
Now we have to calculate the moles of E by comparing the stoichiometry of the compound.
The given compound formula is, [tex]E_4S_{10}[/tex]
As, 10 moles of sulfur combine with 4 moles of E
So, 2.265 moles of sulfur combine with [tex]\frac{2.265}{10}\times 4=0.906[/tex] moles of E
Thus, the moles of E is, 0.906 moles.
Now we have to calculate the atomic mass of E.
Atomic mass of E = [tex]\frac{\text{ given mass of E}}{\text{ moles of E}}= \frac{27.52g}{0.906mole}=30.4g/mol[/tex]
Thus, the atomic mass of E is, 30.4 g/mol
What volume of carbon monoxide is required to react with 32.5 liters of oxygen gas according to the following reaction? (All gases are at the same temperature and pressure.)
carbon monoxide (g) + oxygen (g) carbon dioxide (g)
Answer:
65 L is the volume of CO required
Explanation:
This is the reaction:
2CO (g) + O₂ (g) → 2CO₂ (g)
We must work with density to solve this problem
Density = Mass / volume
Let's determine the moles of O₂
1.43 g/mL = mass / 32500 mL
Notice, that we had to convert the volume from L, to mL, because the units of density.
Mass of O₂ → 1.43 g/mL . 32500 mL = 46475 g
Let's convert the mass to moles (mass / molar mas)
46475 g / 32 g/mol = 1452.3 moles
So ratio is 1:2
1 mol of oxygen needs 2 moles of CO, to react
Then, 1452.3 moles of O₂ would need the double of CO to react
1452.3 moles . 2 = 2904.6 moles of CO
This moles are contained in (mol . molar mass) =
2904.6 mol . 28 g/mol =81328.8 g
Density of CO = Mass of CO/ Volume of CO
1.25 g/mL = 81328.8 g / Volume of CO
81328.8 g / 1.25 g/mL = 65063 mL
If we convert to L
65063 mL = 65.0 L
To react 32.5 liters of oxygen gas with carbon monoxide, the balanced chemical reaction shows a ratio of 2:1 between CO and O₂, thus requiring 65 liters of carbon monoxide.
Explanation:The volume of carbon monoxide required to react with 32.5 liters of oxygen gas can be determined by looking at the coefficients in the balanced chemical equation of the reaction, which is not provided in the question but assuming a typical reaction between carbon monoxide and oxygen to form carbon dioxide, the equation is:
2 CO(g) + O₂(g) → 2 CO₂(g)
This equation shows that 2 volumes of CO react with 1 volume of O₂. Therefore, to find the volume of CO needed for 32.5 liters of O₂, you multiply the volume of O₂ by 2, because the ratio is 2:1.
The required volume of CO = 32.5 liters of O₂ × 2 (because of the ratio 2:1) = 65 liters of CO.