You might be referring to alkali metals.
ExplanationAlkali metals are in group 1 of the periodic table.
Alkali metals have a silvery color. Like nearly all main group metals, they reflect light from the entire visible spectrum.
Each of the group 1 atom have one single valence electron. Removing that electron is easy. They are one electron away from the nearest noble gas element. Removing that extra electron will give the atom an empty valence shell. The atom gains stability through that process.
Alkali metals will readily lose its electrons to non-metals such as oxygen, chlorine, and fluorine. They react with water to form a base and hydrogen gas- hence the name alkali. They are too reactive to exist in nature as metals. That's one of the reasons why power packs containing lithium (an alkali metal) should not be cut open at home. They might catch fire when exposed to the air and have a good chance of creating an explosion.
Alkali metals have low m.p. and b.p. among all the metals. They are easy to cut under room temperature. The softness (a.k.a. malleability), melting point, and boiling point of a metal depends on the strength of the bond between its atoms. Each of the group 1 alkali metal atom has one single electron, whereas metals like aluminum have three. Metallic bonds between alkali metal atoms are much weaker than those between aluminum atoms. As a result, it takes less energy to pull alkali metal atoms apart. They are easier to melt, boil, or cut than metals from other groups. For example, it is possible to tear a chunk of sodium but not iron apart by hand.
Alkali metals are likely to be less dense than any other metals on the periodic table. Elements from the same period have an equal number of electron shells. Alkali metals have less protons per atom than elements from the rest of the period. They weakly attract their electron shells and have a large atomic and ionic radius. An alkali metal will have a lofty structure, while metals to the right of the period are more tightly packed. Alkali metals will have less mass per unit space and have a lower density. For example, typical power banks contain lithium ions rather than nickel. Lithium is lighter than nickel; it allows the battery pack to store more energy per unit mass.
Alkali metals are silvery, soft, highly reactive elements with low melting and boiling points, and are found in Group 1 of the periodic table. These include lithium, sodium, potassium, rubidium, cesium, and francium.
Explanation:The silvery metals that are soft, highly reactive, and too reactive to be found free in nature, characterized by low melting and boiling temperatures, and low densities, are known as alkali metals. These elements make up Group 1 of the periodic table and include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). Alkali metals react rapidly with water to form hydroxides and hydrogen gas, and they must be stored under oil to prevent reactions with moisture and oxygen from the air.
Their reactivity is due to having one electron in their outermost energy level, which they can easily lose to form positive ions with a charge of +1.
explain why a suspension is considered a heterogeneous mixture.
Which electrons in a calcium atom in the ground state have the greatest effect on the chemical properties of calcium
Answer is: the two electrons in the fourth shell.
Atomic number of calcium is 20, it means that it has 20 protons and 20 electrons, so atom of calcium is neutral.
Electron configuration of calcium atom: ₂₀Ca 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²; calcium has two valence electrons (4s²).
In reactions it lose those two electrons ang form cation with positive charge 2+.
Atomic number is the number of protons, which is characteristic of a chemical element.
Beryllium, magnesium,calcium and strontium are alkaline earth metals. The elements have very similar properties.
Alkaline earth metals have in common an outer s- electron shell (two electrons).
Valence electrons have the greatest effect on the chemical properties of calcium
Further explanationElectrons can move the shell up or down by releasing energy or absorbing energy
Excited electrons show higher electron transfer to the shell by absorbing energy
So it can be concluded that there are 2 conditions:
Ground state is the state of electrons filling skins with the lowest energy levels.
Excited state is the state of electrons which occupies a higher energy level
The state of excited electrons can be seen from the presence of electrons which do not fill the skin completely but fill the skin afterwards
Ca has atomic number 20 so the electron configuration is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
This configuration can be said in Ground state conditions
Elemental properties can be determined by its valence electrons (electrons which fill electrons in the outer shell)
The valence electrons of an element indicate in what group and period the element is located in the periodic system so that its properties can be determined
The period of an element is determined from the valence shell (the biggest main quantum number (n) )
Groups of chemical elements are divided into two, namely:
Group A, occupying sub shell s and p
Group B, occupying sub shell d
If we look at valence electrons from Ca atoms then:
period = 4 group = 2ASo that the Ca Atom is located in the alkaline earth group, together with beryllium (Be), magnesium (Mg), strontium (Sr), barium (Ba), and radium (Ra)
So the chemical properties of calcium :
- forming bases - reactive - strong reducing agentLearn moreelement X
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Give the correct thermochemical equations for a (cacl2+h2o) pack and (nh4no3+h2o) pack.
In a pack of CaCl2 and H2O, hydrolysis of Ca+2 will occur
This will result in formation of Ca(OH)2.
The reaction is exothermic in nature
so the balanced thermo-chemical equation will be
CaCl2(aq) + H2O (l) ---> Ca(OH)2 + 2HCl + Heat
In a pack of NH4NO3 and H2O hydrolysis of NH4+ will occur as
NH4NO3 (aq) + H2O(l) + Heat ---> NH4OH(aq) + HNO3 (aq)
It is an endothermic reaction
Copper wire is used in electrical wiring because the metallic bonding between the atoms aids with the ___________ of the material.
Final answer:
Copper wire is used in electrical wiring because its metallic bonding aids with conductivity of the material.
Explanation:
The metallic bonding between the atoms aids with the conductivity of the material.
Copper wire is used in electrical wiring because it has high electrical conductivity. Metallic bonding is responsible for the free flow of electrons in copper, allowing it to conduct electricity efficiently. This property makes copper an ideal material for conducting electric current in various appliances.
Shannon needs 9 feet of ribbon for an art project. How many inches of ribbon should she buy if she is making 4 projects
432 inches
Each project is 9 feet, and she is making 4 projects, so multiply 9 by 4 to find the number of feet needed. You should get 36. Each foot is equal to 12 inches, so multiply 36 by 12 to get 432 inches.
Answer: 432 inches
Explanation:
Given : length of ribbon needed by Shannon for an art project = 9 feet
As we know : 1 feet = 12 inches
9 feet =[tex]\frac{12}{1}\times 9=108inches[/tex]
Thus if for 1 project , length of ribbon required is = 108 inches
For 4 projects , length of ribbon required is =[tex]\frac{108}{1}\times 4=432inches[/tex]
Thus 432 inches of ribbon should she buy if she is making 4 projects.
Suppose the volume of a container is decreased, but the same number of gas molecules is present at the same temperature. What will happen to the molecules?
The molecules will increase in number.
The molecules will decrease in number.
There will be more molecules per unit volume.
There will be less molecules per unit volume.
Answer: Option (C) is the correct answer.
Explanation:
When the volume of a container is decreased and same number of gas molecules are present inside the container at the same temperature then it means that more number of gas molecules are spread per unit volume.
As earlier when the volume of container was more then the molecules were widely spread inside the container but on decreasing the volume of container, molecules come closer to each other and hence there will be increase in molecules per unit volume.
Answer:
It is C
Explanation:
The following solutions are prepared by dissolving the requisite amount of solute in water to obtain the desired concentrations. Rank the solutions according to their respective osmotic pressures in decreasing order assuming the complete dissociation of ionic compounds. Rank from highest to lowest osmotic pressure. To rank items as equivalent, overlap them. 1M C6H12O6, 1M MgCl2, 2M CH3OH, 1M NaCl
Answer:
C₆H₁₂O₆ < NaCl ≈ CH₃OH < MgCl₂
Step-by-step explanation:
The formula for osmotic pressure (Π) is
Π = icRT
If T is constant,
Π = kic
C₆H₁₂O₆:
Π = k × 1 × 1 = k
MgCl₂:
Π = k × 3 × 1 = 3k
CH₃OH:
Π = k × 1 × 2 = 2k
NaCl:
Π = k × 2 × 1 = 2k
The order of osmotic pressures is
C₆H₁₂O₆ < NaCl ≈ CH₃OH < MgCl₂
MgCl₂ > NaCl = CH₃OH > C₆H₁₂O₆ or MgCl₂ > CH₃OH = NaCl > C₆H₁₂O₆.
Further explanationGiven:
1 M C₆H₁₂O₆1 M MgCl₂2 M CH₃OH1 M NaClQuestion:
Rank the solutions according to their respective osmotic pressures in decreasing order assuming the complete dissociation of ionic compounds.
The Process:
The osmotic pressure of a nonelectrolyte solution is calculated as follows:
[tex]\boxed{ \ \pi = MRT \ }[/tex]
The osmotic pressure of an electrolyte solution is calculated as follows:
[tex]\boxed{ \ \pi = MRTi \ }[/tex]
The van't Hoff factor is i = 1 + (n - 1)α, with
n = number of ions, and α = degree of dissociation.In our problem, assuming the complete dissociation of ionic compounds results in α = 100% and i = n.
From the information above, each type of solution can be prepared as follows:
C₆H₁₂O₆ (glucose) and CH₃OH (methanol) are non-electrolyte solutions.MgCl₂ and NaCl are strong electrolyte solutions.[tex]\boxed{ \ MgCl_2 \rightarrow Mg^{2+} + 2Cl^- \ } \rightarrow \boxed{ \ i = n = 3 \ ions \ }[/tex][tex]\boxed{ \ NaCl \rightarrow Na^{+} + Cl^- \ } \rightarrow \boxed{ \ i = n = 2 \ ions \ }[/tex]Now we compare the amount of osmotic pressure from each solution.
1 M C₆H₁₂O₆ ⇒ [tex]\boxed{ \ \pi = 1 \times RT \ } \rightarrow \boxed{ \ \pi = RT \ }[/tex] in atm.1 M MgCl₂ ⇒ [tex]\boxed{ \ \pi = 1 \times RT \times 3 \ } \rightarrow \boxed{ \ \pi = 3RT \ }[/tex] in atm.2 M CH₃OH ⇒ [tex]\boxed{ \ \pi = 2 \times RT \ } \rightarrow \boxed{ \ \pi = 2RT \ }[/tex] in atm.1 M NaCl ⇒ [tex]\boxed{ \ \pi = 1 \times RT \times 2 \ } \rightarrow \boxed{ \ \pi = 2RT \ }[/tex] in atm.From the above results, it can be observed that 2 M CH₃OH and 1 M NaCl have the same osmotic pressure.
Thus, the rank of the solutions according to their respective osmotic pressures in decreasing orders is MgCl₂ > NaCl = CH₃OH > C₆H₁₂O₆ or MgCl₂ > CH₃OH = NaCl > C₆H₁₂O₆.
- - - - - - - - - -
Notes:
Colligative properties are physical properties of a solution that depend on the amount of solute expressed as concentration. One of the colligative properties is osmotic pressure (π).Osmosis is a spontaneous process in which a solvent molecule passes through a semipermeable membrane from a dilute solution (lower solute concentration) to a more concentrated solution (higher solute concentration). The pressure that causes the osmosis process to stop is considered osmotic pressure. We can also observe osmotic pressure as the external pressure needed to prevent the osmosis process. The required external pressure is the same as the osmotic pressure of the solution.Learn moreAbout electrolyte and nonelectrolyte solutions https://brainly.com/question/5404753Calculating the pH value of weak base https://brainly.com/question/9040743To make a 0.500 M solution, one could take 0.500 moles of solute and add? https://brainly.com/question/10278982Why is energy required to remove an electron from an atom?
Electrons in an atom are held there by the force of attraction exerted by the positive charge of the nucleus on the negative charge of the electron. Energy is required to remove an electron from atom to overcome this attractive force.
How do you think bubbles affect sound in the global ocean?
Final answer:
Bubbles in the ocean alter sound propagation by scattering and absorbing sound, which affects acoustic communication and the operation of sonar. Increased bubbles from thermal pollution can also decrease dissolved oxygen levels, impacting marine life.
Explanation:
The presence of bubbles in the global ocean can significantly affect sound propagation. Bubbles can scatter and absorb sound, altering its speed and direction. Consequently, this can influence acoustic communication and the effectiveness of sonar systems used by marine animals and humans for navigation, communication, and detection. For instance, dolphins rely on echolocation to navigate and hunt in the ocean, and bubbles can disrupt the transmission of these sound waves. Additionally, in areas with a high bubble content due to thermal pollution or natural gas seepage, sound may not travel as predictably, which could have navigational implications for sea life and technological systems.
Another aspect where bubbles can play a role is during thermal pollution events, where the solubility of gases in water decreases as the water temperature increases. This leads to the formation of more bubbles, which can reduce the amount of dissolved oxygen in the water, critically affecting marine life. Moreover, sonar technology, which relies heavily on the transmission of sound for detecting objects underwater, can be affected by the presence of bubbles as they change the medium through which sound waves travel. This can make the sonar less precise or reliable.
What is the three-dimensional shape of the molecule with this Lewis structure.
H-Be-H
A. Bent
B. Linear
C. Tetrahedral
D. Trigonal Plannar
I would have to say B. Linear
I hope this helps!
Cheers, July.
Answer : The correct option is, (B) Linear
Explanation :
Formula used :
[tex]\text{Number of electrons}=\frac{1}{2}[V+N-C+A][/tex]
where,
V = number of valence electrons present in central atom
N = number of monovalent atoms bonded to central atom
C = charge of cation
A = charge of anion
Now we have to determine the hybridization of the [tex]BeH_2[/tex] molecules.
[tex]\text{Number of electrons}=\frac{1}{2}\times [2+2]=2[/tex]
The number of electrons is 2 that means the hybridization will be [tex]sp[/tex] and the electronic geometry of the molecule will be linear.
The three-dimensional shape of the molecule with the Lewis structure are shown below.
What is the name for the Fe2+ cation?
Iron ion
Iron (II) ion
Ironide
Ferride ion
Answer:
Iron (II) ion.
Explanation:
Fe²⁺ is a cation of ion that lost 2 electrons.It can be named as iron (II) ion.Iron is the name of the metal, and (II) means that it is the cation of Fe metal that lost 2 electrons.While Iron ion may be Fe²⁺ or Fe³⁺.So, the right choice is: iron (II) ion.
Answer:
The correct answer is the option: Iron (II) ion.
Explanation:
Hello! Let's solve this!
El Hierro (Fe) has two valence numbers. Fe + 2 and Fe +3.
The +2 and +3 indicate that iron lost two or three electrons respectively.
In this case the ion is Fe + 2, this cation is called the Iron (II) ion
We conclude that the correct answer is the option: Iron (II) ion.
A 0.1326 g sample of magnesium was burned in an oxygen bomb calorimeter. the total heat capacity of the calorimeter plus water was 5,760 j/°c. if the temperature rise of the calorimeter with water was 0.570°c, calculate the enthalpy of combustion of magnesium. mg(s) + 1/2o2(g) →mgo(s)
The enthalpy of combustion of magnesium is -601.3 kj/mol
calculation
ΔH = cΔT
C( heat capacity) =5,760 j/°c
ΔT = 0.570°c
ΔH = 5760 j/°c x 0.570 °c = 3283.2 j
convert 3283.2 j into Kj
1 kj = 1000 j
kj ? =3283.2 j
by cross multiplication
={ (3283.2 j x 1 kj) / 1000 j} =3.2832 kj
Find the moles of Mg
moles = mass÷ molar mass
from periodic table the molar mass of Mg = 24.3 g/mol
= 0.1326 g÷ 24.3 g/mol =0.00546 moles
find ΔH in KJ/mol
= 3.2832 kj/ 0.00546 moles = 601.3 Kj/mol
since heat is released during combustion the ΔH is = - 601.3 kj/mol
Which of the following is equal to the number of particles in 36 grams of carbon-12?
B. 3 moles
A. 3:1 molar mass
C. 3:1 mole ratio
D. 1:3 molar volume
The quick answer is B
3 moles
A mole has an alternate definition of 6.02 * 10^23 particles or atoms (in this case) that make it up.
A is possible, but it is not the question.
C is possible, but it is not the question.
I've never directly seen D before. It is used with gases (indirectly).
how did quantum mechanics change our understanding of atoms?
A. in quantum mechanics, electrons exist in a cloud-shaped area outside the nucleus.
B. in quantum mechanics, photons exist in a cloud-shaped area outside the nucleus.
C. in quantum mechanics, photons are a part of the nucleus along with electrons.
D. in quantum mechanics, photons are a part of the nucleus along with protons.
Answer:
The correct answer is option A.
Explanation:
Schrodinger proposed the mechanic model of atom in which he defined the location of electrons inside an atom by electron cloud in 3-d space. And in order to locate them he introduced the concept of quantum numbers.
Where as photons are the discrete packet or bundle of energy related to electromagnetic radiations.
An electron and a proton attract each other as a result of _____ forces.
a. inertial
b. gravitational
c. compression
d. electromagnetic
The correct answer is D. Electromagnetic
Explanation:
Electron and protons are both subatomic particles that differ in their mass and other features including electromagnetic charges. Indeed, protons are positively charged, while electrons are negatively charged. This difference in electromagnetic charges causes electrons to be attracted to electrons, and vice versa due to electromagnetic forces as particles with different charges attract each other while those with the same charges repel each other. Thus, an electron and a proton attract each other as a result of electromagnetic forces.
Sea turtles are found in the waters of Georgia. Building on the coast has destroyed their nesting sites. How will this MOST LIKELY affect the sea turtles usually found on the Georgia coast?
A) The turtles will begin laying more eggs.
B) The turtles will build nests in other places.
C) The turtles will no longer be found in Georgia.
D) This will not affect the number of turtles in Georgia.
The correct answer is option C, that is, the turtles will no longer be found in Georgia.
Due to the presence of protected dunes and temperate climate appropriate for nesting activities, the barrier island beaches of Georgia host an average of 1000 sea turtles nests in a year.
However, the main danger to sea turtles in Georgia is the damage of their eggs and nests and offshore mortalities related to commercial longline fishing or shrimping activities. With the development going on in the coastal regions where the turtles thrive, a time will come when one will no longer witness any turtle along the coast of Georgia.
Answer:
C
Explanation:
The turtles will no longer be found in Georgia.
A non-native organism that is released into a new ecosystem, such as Kudzu in the southeastern United States is called a
A) pioneer species.
B) threatened species.
C) endangered species.
D) non-indigenous species.
Answer is: D) non-indigenous species.
Non-indigenous species or an introduced species is a species living outside its native area, but which has arrived there by human activity, either deliberate or accidental.
Kudzu (Japanese arrowroot) was introduced from Japan into the United States at the Japanese pavilion in the 1876 Centennial Exposition in Philadelphia.
The United States Forest Service estimated the rate of spreading of plant Kudzu to be 2500 acres per year.
Answer:
D. non-indigenous species.
Explanation:
When so much solute is added that no more will dissolve, what type of solution has been created? NEED HELP ASAP
The simplest answer and the correct one is saturated. You can try this at home to see what it looks like. Take a glass and fill it to the 1/2 full mark. Make sure the water is on the coolish side. Start putting measured amounts of salt in the water. Do this until you see salt on the bottom of the glass. The solution is now saturated.
Empty the glass. Put the same amount of water in the glass but make it much warmer. Put the same amount of salt in the glass. It should not be saturated -- that is there should be no salt on the bottom.
So temperature determines saturation. But more important, you should get an idea of what saturation is.
Evaluate why acids are able to conduct electricity. Then describe which types of acids are better conductors and why.
Acids produce H+ ions in solution.
Since it produces ions in solution and ions can carry current.
Hence acids can conduct electricity as it produces ions in solution.
Strong acids dissociate completly and produce more ions (than weaker acids which do not dissociate completly) so strong acids are better conductors of electricity.
Complete the paragraph to describe the characteristics of silicon tetrachloride molecule (SiH4). the Lewis structure and the table of electronegativities are given.
The bond polarities of SiH4 are _____, the molecular shape is _____, and the molecule is _____.
Blank Options 1: Polar, Nonpolar
Blank Options 2: trigonal pyramidal, trigonal planar, tetrahedral, linear, bent
Blank Options 3: Polar, Nonpolar
Silicon tetrachloride (SiH4) is a covalent tetrahedral molecule with a trigonal pyramidal shape. It is nonpolar and has a low boiling point of 57 °C.
Explanation:Silicon tetrachloride (SiH4) is a covalent tetrahedral molecule with a trigonal pyramidal shape. The Lewis structure for SiH4 would show the silicon atom in the center with four chlorine atoms bonded to it. Each chlorine atom would have a lone pair of electrons, causing the molecule to have a trigonal pyramidal shape.
The electronegativity values of silicon and chlorine are 1.9 and 3.2 respectively, indicating a polar covalent bond between silicon and chlorine. However, due to the symmetry of the molecule, the dipole moments cancel each other out, resulting in a nonpolar molecule. Silicon tetrachloride is a colorless liquid with a low boiling point of 57 °C.
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Silicon tetrahydride (SiH4) is a nonpolar molecule with a tetrahedral shape due to the central silicon atom being sp³ hybridized. Even though Si-H bonds are polar, the symmetry of the molecule results in a nonpolar overall molecule.
Explanation:The bond polarities of SiH4 are Nonpolar. SiH4, or Silicon tetrahydride, is a covalent molecule with tetrahedral structure, in which Silicon (Si) forms four single bonds with four Hydrogen (H) atoms. Central Silicon atom is sp³ hybridized, which results in a Tetrahedral molecular shape. Even though the Si-H bonds are polar because of the difference in electronegativities of Si and H, the bond dipoles cancel each other because of the molecule's symmetry, making the whole molecule Nonpolar.
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Which compound is held together by ionic bonds?
A. S02
B. H20
C. CaCl2
D. CH4
Answer is: C. CaCl2.
Name of this chemical compounds is calcium chloride.
Calcium chloride is a inorganic salt with ionic bonds between calcium and chlorine.
It is a colorless crystalline solid at room temperature, highly soluble in water.
Calcium form cation with positive charge 2+ and chlorine form anion with negative charge 1-.
Electron configuration of calcium atom: ₂₀Ca 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
Atomic number of calcium is 20, it means that it has 20 protons and 20 electrons, so atom of calcium is neutral.
When calcium lost two electrons, it will have 20 protons (positive charge) and 18 electrons (negative charge), which means it has two protons more and it has +2 oxidation number.
How has the discovery and usage of the periodic table benefited society?
Select all that apply.
It has enabled scientists to communicate chemical discoveries and results more easily.
It has increased scientists' ability to determine how cations and anions form covalent bonds.
It has increased scientists' ability to predict and discover new elements.
It has led to increased knowledge and usage of elements in technological innovations.
Final answer:
The discovery and usage of the periodic table has benefited society by enabling easy communication of chemical discoveries, predicting and discovering new elements, and driving technological innovations.
Explanation:
The discovery and usage of the periodic table has benefited society in several ways:
It has enabled scientists to communicate chemical discoveries and results more easily. The organized structure of the periodic table allows for efficient sharing of information between researchers.It has increased scientists' ability to predict and discover new elements. By identifying the patterns and trends in the periodic table, scientists can make educated guesses about the existence and properties of elements that have not yet been discovered or synthesized.It has led to increased knowledge and usage of elements in technological innovations. The periodic table provides a framework for understanding the behavior of different elements, allowing scientists to develop new materials and technologies.Why is a bush or tree a more accurate then a line to describe how hominds developed into modern humans
The human “family tree” may be better described as a “family bush,” within which it is impossible to connect a full chronological series of species, leading to Homo sapiens, that experts can agree upon.
A substance registers a temperature change from 20°c to 40°c. to what incremental temperature change does this correspond?
The incremental temperature change is 20°C or 50%.
What is incremental temperature change ?Incremental temperature change is the change in the temperature of any substance when it is increased from its original temperature. Incremental temperature change is always measured as percentage increase in the rate of temperature.
How to calculate the incremental temperature change ?Temperature is increased from 20°C to 40°C .
Thus incremental change in temperature,
ΔT = Final temperature - Initial temperature
∴ ΔT = 40°C - 20°C = 20°C
Also percentage change in temperature ,
(ΔT / Final temperature) × 100 %
⇒ (20°C / 40°C) × 100 %
⇒ (1/2) × 100 %
∴ Percentage change = 50%
Thus incremental temperature change is 20°C or 50%
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Do you think that the mole should be considered a base unit in the SI system? Explain why or why not.
The International System of Units (S.I.) is the modern form of the metric system, and is the most widely used system of measurement.
It comprises a coherent system of units of measurement built
- on seven base units, which are
(the ampere, kelvin, second, metre, kilogram, candela, mole)
- a set of twenty prefixes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units.
The system also specifies names for 22 derived units, such as lumen and watt, for other common physical quantities.
So, the mole not should be .... is a base unit in the SI system
Yes, the mole should be considered as a base unit in the SI unit.
A mole is defined as the physical properties of the real object, the carbon atom. Therefore, it is a base unit.
Mole as a base unit in the SI systemA Mole is a base unit of substances in the international SI unit.It is defined as a collection of exactly 6.022140761023 elementary entities (particles), which can be atoms, molecules, ions, or electrons.Thus, the mole is considered as a base unit in the SI system, because it defined as physical properties of real objects.
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Ce procent de impuritati contine un minereu de siderit, daca din 1500kg minereu s-au obtinut 700kg fier 90% ?
FeCO3 ==> Fe + produsi minoritari.
m Fe impur= 700 kg
puritatea (p) = masa pura (mp)/ masa impura (mi) x 100
mp= p x mi / 100 sau mp = p/100 x mi => mp Fe = 90/100 x 700 = 630 kg Fe pur.
M FeCO3= 115.85 kg/kmol
115.85 kg FeCO3 .... 55.85 kg Fe
x kg FeCO3 ........630 kg Fe
x= 630 * 115.85 /55.85 = 1306.81 kg FeCO3 (mp in formula puritatii)
p=mp/mi x 100
mi FeCO3 = 1500 kg
mp FeCO3=1306.81 kg
p=1306.81 / 1500 x 100 = 87.12% puritate Siderit
PLEASE HELP ASAP!!THANKS!
Balance the following and label what type of reaction is taking place:
C5H9O + O2? CO2 + H2O
The given reaction is C₅H₉O + O₂ → CO₂ + H₂O
On balancing the equation we get:
20 C₅H₉O + 90 O₂ → 100 CO₂ + 9 H₂O
This is a single replacement type of reaction. A single replacement reaction, also called a single-displacement reaction, refers to a kind of chemical reaction where an element reacts with a compound and occupies the place of another element in that compound.
Triethylenemelamine is used in the plastics industry and as an anticancer drug. Its analysis is 52.93% carbon, 5.92 % hydrogen, 41.15% nitrogen. The molecular mass of triethylenemelamine is 204.2 g/mol. What is its empirical formula? What is its molecular formula?
Assuming total mass to be 100 g
Mass of C = 52.93 g
=> Moles of C = [tex]52.93 g *\frac{1 mol}{12gC} =4.41 mol C[/tex]
Mass of H = 5.92 g
=> Moles of H=[tex]5.92g*\frac{1mol}{1.01g}=5.86molH[/tex]
Mass of N = 41.15 g
=>Moles of N=[tex]41.15g*\frac{1 mol}{14 g}=2.94mol N[/tex]
Simplest mole ratio of the atoms in the compound:
[tex]C_{\frac{4.41mol}{2.94mol} } H_{\frac{5.86mol}{2.94mol} }N_{\frac{2.94mol}{2.94mol} } =C_{1.5}H_{2}N_{1} or(C_{1.5}H_{2}N_{1})_{2}=>C_{3}H_{4}N_{2}[/tex]
Empirical formula mass=[tex](3*12)+(4*1.01)+(2*14)=68.04g[/tex]
Multiple n = [tex]\frac{204.2}{68.04}=3[/tex]
Molecular formula= [tex](Empirical formula)_{n} =(C_{3}H_{4}N_{2})_{3}=C_{9}H_{12}N_{6}[/tex]
Final answer:
The empirical formula of triethylenemelamine is determined to be C₃H₄N₂ based on the given percentage composition. By comparing the molecular mass of triethylenemelamine to the mass of the empirical formula unit, the molecular formula is found to be C₆H₈N₄.
Explanation:
To determine the empirical formula and molecular formula of triethylenemelamine based on its percent composition (52.93% carbon, 5.92% hydrogen, 41.15% nitrogen) and molecular mass (204.2 g/mol), follow these steps:
Calculate the moles of each element based on 100 g of the compound.
For Carbon: (52.93 g / 12.01 g/mol) = 4.41 moles
For Hydrogen: (5.92 g / 1.008 g/mol) = 5.87 moles
For Nitrogen: (41.15 g / 14.01 g/mol) = 2.94 moles
Determine the simplest whole number ratio of the elements by dividing by the smallest number of moles, which in this case is 2.94 moles (N). This gives:
C: 4.41 / 2.94 ≈ 1.5
H: 5.87 / 2.94 ≈ 2
N: 2.94 / 2.94 = 1
Since the ratio needs to be in whole numbers, multiply each by 2 to get C₃H₄N₂ as the empirical formula.
To find the molecular formula, divide the molecular mass of triethylenemelamine (204.2 g/mol) by the mass of the empirical formula unit (C₃H₄N₂ = 3(12.01) + 4(1.008) + 2(14.01) ≈ 84.1 g/mol), getting approximately 2.43. Since molecular formulas must be whole numbers, this indicates the empirical formula must be multiplied by 2, giving C₆H₈N₄ as the molecular formula of triethylenemelamine.
ASAP
Which of the following would have the greatest mass?
15.0 moles of N
5.0 moles of Zn
20.0 moles of H
1.0 moles of Pb
In order to find the mass (in grams) of an element, you just need to multiply the no. of moles given by the atomic mass of the element, which can be found in a periodic table.
mass of 15.0 moles of N= 15.0 x 14.0 = 210g
mass of 5.0 moles of Zn= 5.0 x 65.4 = 327g
mass of 20.0 moles of H= 20.0 x 1.0 = 20g
mass of 1.0 moles of Pb= 1.0 x 207.2 = 207.2g
Therefore, since 327g is the greatest mass out of the 4 options, the answer is 5.0 moles of Zn.
For the reaction Na + H2O → NaOH + H2, what are the reactants, products, and correct coefficients in the balanced equation? Reactants: 1Na and 1H2O; products: 1NaOH and 1H2 Products: 2Na and 1H2O; reactants: 2NaOH and 1H2 Products: 3Na and 2H2O; reactants: 3NaOH and 2H2 Reactants: 2Na and 2H2O; products: 2NaOH and 1H2
The correct answer is reactants 2Na and 2H₂O and products 2NaOH and 1H₂.
The given unbalanced chemical equation is:
Na (s) + H2O (l) → NaOH (aq) + H₂ (g)
From the equation, it can be seen that there are three atoms of hydrogen on the products side, however, only two on the reactant's side. So, in order to balance the equation, one needs to multiply the sodium hydroxide by 2 to get a total of 4 atoms of hydrogen on the product's side.
This will enable one to readily double the number of molecules of water to get 4 atoms of hydrogen on the reactants side, and then balance the atoms of sodium by multiplying the sodium metal by 2. The balanced equation obtained is:
2Na (s) + 2H₂O (l) → 2NaOH (aq) + H₂ (g)
In the given chemical reaction, Reactants: 2Na and 2H₂O and Products: 2NaOH and 1H₂. Therefore, option D is correct.
In the balanced equation, the coefficients indicates the relative number of moles of each substance involved in the reaction. The balanced equation for the reaction between sodium (Na) and water (H₂O) to produce sodium hydroxide (NaOH) and hydrogen gas (H₂) is: 2Na + 2H₂O → 2NaOH + H₂
This balanced equation shows that 2 moles of sodium reacts with 2 moles of water to produce 2 moles of sodium hydroxide and 1 mole of hydrogen gas.
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