Answer:
[tex]\boxed{\text{True; False; True}}[/tex]
Explanation:
Catalysts lower activation energy. TRUE.
They provide an alternate pathway with a lower activation energy.
Catalysts are consumed by the overall reaction. FALSE.
They take part in the reaction, but they can be recovered unchanged at the end.
Catalysts speed up the chemical reactions. TRUE.
If the activation energy is lowered, a greater percentage of the molecules will have enough energy to get over the energy barrier.
Its like lowering the high-bar in a track and field meet. The lower the bar, the more athletes will be able to get over it.
1. Including a full-wave rectifier in an AC circuit will yield a/an _______ current.
A. continuous alternating
B. continuous direct
C. intermittent alternating
D. intermittent direct
2. A transmission system at a radio station uses a/an _______ to convert a direct current into a high-frequency alternating current.
A. modulator
B. oscillator
C. demodulator
D. transmitting antenna
3. Combining which of the following substances with germanium will cause the germanium to emit free electrons?
A. Indium
B. Gallium
C. Bismuth
D. Aluminum
6. Which of the following does not affect the electrical resistance of a body?
A. Bodies directly surrounding the body
B. Length of the body
C. Temperature of the body
D. Material composing the body
8. Which of the following is an accurate description of the relationship demonstrated in Ohm's Law?
A. The resistance (ohms) divided by the current (amperes) equals the electric potential (volts).
B. The electric potential (volts) divided by the current (amperes) equals the resistance (ohms).
C. The electric potential (volts) multiplied by the resistance (ohms) equals the current (amperes).
D. The electric potential (amperes) divided by the resistance (ohms) equals the current (volts).
11. A series circuit contains a generator, two devices, and connecting wires. The resistances of the two devices are 15 ohms and 10 ohms. The voltage supplied by the generator is 75 V. What will be the voltage drop in the device with 10 ohms of resistance?
A. 3 V
B. 45 V
C. 25 V
D. 30 V
13. If a bar magnet's neutral region is broken in two, what will most likely occur?
A. Each of the two segments of the original bar magnet will have a north and south pole.
B. The segment that's longer will have a north and south pole.
C. One segment will have only a north pole, the other segment will have only a south pole.
D. Neither segment will have a north or south pole
16. Which of the following would decrease the resistance to the flow of an electric current through a body?
A. Using a conductor with a smaller cross section
B. Lengthening the conductor
C. Shortening the conductor
D. Heating the conductore
each question is worth 5 points I will give brainliest answer
1) B) continuous direct.
2) B) oscillator.
3) C) Bismuth.
6) I dont know this one sorry :/
8) B) The electric potential (volts) divided by the current (amperes) equals the resistance (ohms).
11) D) 30 V
13) A) Each of the two segments of the original bar magnet will have a north and south pole.
16) C) Shortening the conductor.
The chemical element found in all amino acids but not found in either carbohydrates or fats is
Answer:
Nitrogen
Explanation:
What is the oxidation number of chromium in k2cr2o7
Answer:
The oxidation state of chromium in K₂Cr₂O₇ is 6⁺ (i.e. + 6).Explanation:
You can calculate the oxidation number of most elements following some simple rules.
This is how you do it for chromium in K₂Cr₂O₇.
1) Rule: in a neutral compound the net oxidation number is zero (0).
Hence, sum of the oxidation numbers of K, Cr and O in K₂Cr₂O₇ is 0.
2) Rule: The most common oxidation number of oxygen in compounds, except in peroxides, is 2 ⁻ (negative 2).
3) Rule: the most common oxidation state of alkali metals is 1⁺ (positive 1)
4) Rule: multiply each oxidation state by the corresponding number of atoms in the compound (the subscripts)
2(1⁺) + 2(x) + 7(2⁻) = 0↑ ↑ ↑
K Cr O
2 + 2x - 14 = 02x - 12 = 02x = 12x = 6Hence, the oxidation number of chromium in this compound is 6⁺.
The oxidation number of chromium in K2Cr2O7 (potassium dichromate) is +6. This is determined by knowing that potassium has an oxidation number of +1, oxygen has an oxidation number of -2, and the sum of the oxidation numbers of the chromium atoms must balance the charge contributed by potassium and oxygen to make the compound neutral.
Explanation:The oxidation number of chromium in K2Cr2O7 requires some calculation using the rules of oxidation states. Firstly, potassium (K) has an oxidation number of +1, and each oxygen (O) has an oxidation number of -2. In the compound K2Cr2O7, there are two potassium atoms contributing a total of +2 to the charge of the compound. There are seven oxygen atoms each contributing -2, for a total of -14. Since the compound is neutral overall, the sum of the oxidation numbers of the chromium atoms must balance the negative charge contributed by the oxygen. Therefore, the total oxidation state for the two Cr atoms must be +12 in order to have a net charge of zero when added to the oxidation states of potassium and oxygen. Dividing this by two, since there are two chromium atoms, gives an oxidation number of +6 for each chromium atom.
Additionally, in the reduction half-reaction, Cr2O72- is reduced to Cr3+ with each chromium atom being in the +6 oxidation state initially. The chemical reaction involving the conversion of Fe2+ to Fe3+ supported by potassium dichromate provides further evidence that each chromium atom has an initial oxidation state of +6.
C3H8 + 5O2 → 3CO2 + 4 H2O
How many moles of C3H8 must be reacted to form exactly 10.0 g of H2O?
0.139 mol
0.250 mol
40.0 mol
0.400 mol
Answer:
0.139
Explanation:
First find how many moles of h2o give you 10g then use the mole ratio to find what mole of c3h8 is required to get you that number of moles
Answer:
0.139 moles of C3H8 must be reacted to form exactly 10.0 g of H2O
Explanation:
The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.
If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:
a ⇒ b
c ⇒ x
[tex]x=\frac{c*b}{a}[/tex]
It is possible to use the reaction stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction) and the rule of three to determinate the moles of C₃H₈ that must be reacted to form exactly 10.0 g of H₂O. But first you must know the amount of moles that represent the 10 g of H₂O.
You know that:
O= 16 g/molH=1 g/molThen, the mass of H₂O is 2*1 g/mol + 16 g/mol= 18 g/mol
Then it is possible to apply a rule of three: if 1 mole of H₂O contains 18 grams, how many moles will contain 10 grams?
[tex]moles of H2O=\frac{10 grams*1 mole}{18 grams}[/tex]
moles of H₂O=0.556
Then, to determine the moles of C₃H₈ that must react to form exactly 10.0 g of H₂O it is possible to use a rule of three, as previously mentioned: if by stoichiometry 4 moles of H₂O are formed from 1 moles of C₃H₈, when are formed 0.55 moles of H₂O How many moles of C₃H₈ will be needed?
[tex]moles of C3H8=\frac{0.556molesofH2O*1molesofC3H8}{4molesofH2O}[/tex]
moles of C₃H₈= 0.139
Finally, 0.139 moles of C3H8 must be reacted to form exactly 10.0 g of H2O
What is the process that changes one set of chemicals into another set of chemicals
Answer:
A chemical reaction is a process that changes one set of chemicals into another set of chemicals. The elements or compounds that enter into the reaction are the ► reactants. The elements or compounds produced by the reaction are the ► products.
If ice is warmed and becomes a liquid which type of process is it
Answer:
EndothermicExplanation:
Endothermic means that the process makes that the system (substance) absorbs heat energy from the surroundings. In this case the heat is supplied to the ice (from a flame for example). So, the ice is absorbing this heat.
In general, the phase change from solid (ice) to liquid is endothermic because the solid substance has a lower kinetic energy than the liquid particles. So, the solid must gain energy (which is supplied in the form of heat) to become liquid.
The reason why the solid particles have lower kinetic energy than liquid ones is that the particles vibrate and translates quicker in the liquid state than in the solid state.
The molar concentration of sucrose in a can of soda is 0.375 M. How much sucrose would be found in a 2 liter bottle of soda of the same concentration?
A)
0.075 mol
B)
0.19 mol
C)
0.75 mol
D)
1.9 mol
Answer:
C) 0.75 mol.
Explanation:
Molarity is defined as the no. of moles of solute dissolved in 1.0 L of the solution.So, The molar concentration of sucrose in a can of soda is 0.375 M means that: every 1.0 L of sucrose contains 0.375 mol of sucrose.
∴ 2 liter bottle of soda of the same concentration contains (2 * 0.375 mol = 0.75 mol) of sucrose.
Thus, the right choice is: C) 0.75 mol.
I NEED HELP ASAP!!! THIS IS A 30 POINT QUESTION!!!
Which statement best describes the steps leading up to protein synthesis?
( 1 )The translation of DNA to RNA occurs in the cytoplasm; then, the transcription of RNA occurs in the nucleus.
( 2 )The transcription of DNA to RNA occurs in the cytoplasm; then, the translation of RNA occurs in the nucleus.
( 3 )The translation of DNA to RNA occurs in the nucleus; then, the transcription of RNA occurs in the cytoplasm.
( 4 ) The transcription of DNA to RNA occurs in the nucleus; then, the translation of RNA occurs in the cytoplasm.
Answer:
4
Explanation:
Protein synthesis involves two major steps:
Transcription of the DNA to mRNA (a form of RNA)Translation of the mRNA molecule into a protein.Transcription involves the formation of a nucleotide sequence complementary to the DNA molecule, with the pairing of a different base, Uracil, with Guanine instead of the usual Thymine base. This occurs in the nucleus of the cell, and the resulting molecule is known as the mRNA.
This mRNA is transported into the cytoplasm through the nuclear pore for the next step, translation. This is primarily accomplished by ribosomes and tRNA molecules which are present in the cytoplasm of the cell. The result of this step is the generation of a protein molecule.
Hope this helpsAnswer:
its A, C and E (1, 3, 5)
i did this on edgenuiti and it was correct =)
mark as brainliest i really need it bc if not i'll never level up i have 797/500 points
Binary molecular compounds are composed of two ______ elements
Answer:
Non-metal
Explanation:
Molecular compounds are formed through covalent bonds. Covalent bonds occur between non-metals only and they form what we call molecules, hence the name molecular compound.
An example of a molecular compound is carbon monoxide or CO. Carbon is a non-metal and oxygen is a non-metal, so you know that they form a covalent bond.
That's the difference with ionic compounds. Ionic bonds form ionic bonds and these bonds occur between a metal and a non-metal.
Binary molecular compounds are made of two nonmetallic elements and have specific naming conventions such as prefixes to denote the number of atoms.
Binary molecular compounds are composed of two nonmetallic elements. They are named using a specific nomenclature that includes prefixes to indicate the number of atoms of each element present in the compound. For example, carbon dioxide, CO₂, is a binary molecular compound consisting of one carbon atom and two oxygen atoms.
What is meant by the half-life of a radioactive substance
Answer:
Explanation:
The half life of a radioactive atom is the time taken for half of the radioactive nuclei to disintegrate. The shorter the half life, the faster a radioactive nuclei decays.
Half life is often expressed as:
Half life = [tex]\frac{0.693}{λ}[/tex]
Where λ is the decay constant.
What is the Ka of 0.168M solution of Hydrocyanic acid (HCN) with pH of 3.15?
The answer is in the photo, but a 0,168 M HCN doesn’t have a pH of 3,15, but 5. HCN real Ka is 6,17*10^(-10).
Answer:
The real answer is 3.00x10^-6
Explanation:
Fill in 3.00 and then -6
A student is performing an experiment to study thermodynamics. The student mixes citric acid and sodium bicarbonate in a calorimeter to determine the energy released in the chemical reaction. In one paragraph, identify the system, the surroundings, and the reasons for using calorimetry in this type of experiment.
Explanation :
In thermodynamics, a system is region or part of space which is being studied and observed while the surrounding is the region or space around the system which interacts with the system.
Here in the experiment ,system which is observed is reaction or changes when citric acid and sodium bicarbonate are mixed together. And the mixing is carried out in the calorimeter which serves as a surrounding around the system.
The reason behind the using the calorimeter is measure the energy change occurring during the reaction.
A molecule of an unsaturated hydrocarbon must have
1) at least one single carbon-carbon bond
2) at least one multiple carbon-carbon bond
3) two or more single carbon-carbon bonds
4) two or more multiple carbon-carbon bonds
Answer:
2) at least one multiple carbon-carbon bond.
Explanation:
An unsaturated hydrocarbon must have a double or triple C-C bond which is unsaturated bond that means it is not saturated with atoms.Saturated hydrocarbon is the hydrocarbon in which all C-C bonds are single.So, A molecule of an unsaturated hydrocarbon must have 2) at least one multiple carbon-carbon bond.
CH4 + 2O2 ? CO2 + 2H2O In the chemical reaction, if 10 moles of H2O are produced, moles of CO2 are also produced.
Answer:
5 moles
Explanation:
This reaction (in the question) is a combustion reaction.
A combustion reaction is a reaction in which a substance (in this case an organic compound) is burnt in excess oxygen to produce carbon dioxide and water.
From the equation in the question, it can be deduced that the moles of the products are in the ratio 1:2 for CO₂ and H₂O respectively. Hence, when 10 moles of H₂O is produced, 5 moles of CO₂ will be produced.
1:2 (from the equation)
5:10 (for the answer) ⇔ which is still the same as 1:2
A 0.100 M solution of K2SO4 would contain the same total ion concentration as which of the following solutions?0.0800 M Na2CO3 0.100 M NaCl 0.0750 M Na3PO4 0.0500 M NaOH
Answer:
The third chice: 0.0750 M Na₂SO₄Explanation:
Assume 100% ionization:
1) 0.100 M solution K₂SO₄
K₂SO4 (aq) → 2K⁺ (aq) + SO₄²⁻ (aq)Mole ratios: 1 mol K₂SO4 : 2 mol K⁺ + 1 mol SO₄²⁻ (aq) : 3 mol ions. This is 1 : 3At constant volume, the mole ratios are equal to the concentration ratios (M).1 M K₂SO₄: 3 M ions = 0.100 M K₂SO₄ / x ⇒ x = 0.300 M ionsThis means, that you have to find which of the choices is a solution that contains the same 0.300 M ion concentration.
2) 0.0800 M Na₂CO₃
Na₂CO₃ (aq) → 2 Na⁺ + CO₃⁻1 M Na₂CO₃ / 3 M ions = 0.0800M / x ⇒ x = 0.0267 M ionsThis is not equal to 0.300 M, so this solution would not contain the same total concentration as a 0.100 M solution of K₂SO₄, and is not the right answer.
3) 0.100 M NaCl
NaCl → Na⁺ + Cl⁻1 M NaCl / 2 M ions = 0.100 M NaCl / x ⇒ x = 0.200 M ionsThis is not equal to 0.300 M ion, so not a correct option.
4) 0.0750 M Na₃PO₄
Na₃PO₄ → 3Na⁺ + PO₄³⁻1 M Na₃PO₄ / 4 M ions = 0.0750 M Na₃PO₄ / x ⇒ x = 0.300 M ionsHence, this ion concentration is equal to the ion concentration of a 0.100 M solution of K₂SO₄, and is the correct choice.
5) 0.0500 M NaOH
NaOH → Na⁺ + OH⁻1 M NaOH / 2 mol ions = 0.0500 M NaOH / x ⇒ x = 0.100 M ionsNot equal to 0.300 M, so wrong choice.
A 0.100 M solution of K₂SO₄ has the same total ion concentration as a 0.0750 M solution of Na₃PO₄, both resulting in 0.300 M of ions.
K₂SO₄ dissociates into 2K⁺ and (SO₄)²⁻. Thus, a 0.100 M solution of K₂SO₄ produces 0.200 M K⁺ (2 x 0.100 M) and 0.100 M (SO₄)₂⁻, resulting in a total ion concentration of 0.300 M.
Let’s analyze the other solutions:
0.0800 M Na₂CO₃: Dissociates into 2 Na⁺ and (CO₃)²⁻, producing 0.160 M Na⁺ and 0.080 M (CO₃)²⁻. Total: 0.240 M ions.0.100 M NaCl: Dissociates into Na⁺ and Cl⁻, producing 0.100 M Na⁺ and 0.100 M Cl⁻. Total: 0.200 M ions.0.0750 M Na₃PO₄: Dissociates into 3 Na⁺ and (PO₄)³⁻, producing 0.225 M Na⁺ and 0.075 M (PO₄)³⁻. Total: 0.300 M ions.0.0500 M NaOH: Dissociates into Na⁺ and OH⁻, producing 0.050 M Na⁺ and 0.050 M OH⁻. Total: 0.100 M ions.The correct answer is 0.0750 M Na₃PO₄, as it also produces a total ion concentration of 0.300 M.
At a certain temperature and pressure, one liter of CO2 gas weighs 1.95 g.
What is the mass of one liter of C2H6 gas at the same temperature and pressure?
Answer:
1.332 g.
Explanation:
We can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
At the same T and P and constant V (1.0 L), different gases have the same no. of moles (n):∴ (n) of CO₂ = (n) of C₂H₆
∵ n = mass/molar mass
∴ (mass/molar mass) of CO₂ = (mass/molar mass) of C₂H₆
mass of CO₂ = 1.95 g, molar mass of CO₂ = 44.01 g/mol.
mass of C₂H₆ = ??? g, molar mass of C₂H₆ = 30.07 g/mol.
∴ mass of C₂H₆ = [(mass/molar mass) of CO₂]*(molar mass) of C₂H₆ = [(1.95 g / 44.01 g/mol)] * (30.07 g/mol) = 1.332 g.
The mass of 1 liter of C2H6 gas at the same temperature and pressure as the CO2 can be calculated using Avogadro's principle and the proportionality of molar masses. You set up a proportion using the molar masses of CO2 and C2H6 and the given weight of CO2 to solve for the weight of C2H6 gas.
Explanation:First, you need to understand the concept of molar mass and Avogadro's principle. Avogadro's principle states that equal volumes of all gases, at the same temperature and pressure, have the same number of molecules.
The molar mass of CO2 is approximately 44.01 g/mol. Given that one liter of CO2 gas weighs 1.95g, we can calculate the molar volume of a gas at the given temperature and pressure. Because the weights will be proportional, we can use the molar mass of C2H6 to find the weight of 1 liter of C2H6 gas.
Since the molar mass of C2H6 (ethane) is approximately 30.07 g/mol, you can set up the proportion as follows: 44.01 / 1.95 = 30.07 / X. Solving this equation gives you the weight of C2H6.
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Use the changes in oxidation numbers to identify which atom is oxidized, reduced, the oxidizing agent, and the reducing agent. 5
A
2H2(g) + O2(g) → 2H2O(l)
B
2KNO3(s) → 2KNO2(s) + O2(g)
Answer:
Reaction A:
Hydrogen atoms in H₂ are oxidized.Oxygen atoms in O₂ are reduced.Hydrogen gas H₂ is the reducing agent.Oxygen gas O₂ is the oxidizing agent.Reaction B:
Oxygen atoms in KNO₃ are oxidized.Nitrogen atoms in KNO₃ are reduced.Potassium nitrate (V) KNO₃ is both the oxidizing agent and the reducing agent.Explanation:
When an atom is oxidized, its oxidation number increases.When an atom is reduced, its oxidation number decreases.The oxidizing agent contains atoms that are reduced.The reducing agent contains atoms that are oxidized.Here are some common rules for assigning oxidation states.
Oxidation states on all atoms in a neutral compound shall add up to 0.The average oxidation state on an atom is zero if the compound contains only atoms of that element. (E.g., the oxidation state on O in O₂ is zero.)The oxidation state on oxygen atoms in compounds is typically -2. (Exceptions: oxygen bonded to fluorine, and peroxides.)The oxidation state on group one metals (Li, Na, K) in compounds is typically +1. The oxidation state on group two metals (Mg, Ca, Ba) in compounds is typically +2.The oxidation state on H in compounds is typically +1. (Exceptions: metal hydrides where the oxidation state on H can be -1.)For this question, only the rule about neutral compounds, oxygen, and group one metals (K in this case) are needed.
Reaction BOxidation states in KNO₃:
K is a group one metal. The oxidation state on K in the compound KNO₃ shall be +1.The oxidation state on N tend to vary a lot, from -3 all the way to +5. Leave that as [tex]x[/tex] for now.There's no fluorine in KNO₃. The ion NO₃⁻ stands for nitrate. There's no peroxide in that ion. The oxidation state on O in this compound shall be -2.Let the oxidation state on N be [tex]x[/tex]. The oxidation state of all five atoms in the formula KNO₃ shall add up to zero. [tex]1\times (+1) + 1 \times (x) + {\bf 3} \times (-2) = 0\\x = +5[/tex]. As a result, the oxidation state on N in KNO₃ will be +5.Similarly, for KNO₂:
The oxidation state on the group one metal K in KNO₂ will still be +1.Let the oxidation state on N be [tex]y[/tex].There's no peroxide in the nitrite ion, NO₂⁻, either. The oxidation state on O in KNO₂ will still be -2.The oxidation state on all atoms in this formula shall add up to 0. Solve for the oxidation state on N: [tex]1\times (+1) + 1 \times (y) + {\bf 2}\times (-2) = 0\\y = +3[/tex]. The oxidation state on N in KNO₂ will be +3.Oxygen is the only element in O₂. As a result,
The oxidation state on O in O₂ will be 0.[tex]\rm\stackrel{+1}{K}\stackrel{\bf +5}{N}\stackrel{\bf -2}{O}_3 \to \stackrel{+1}{K}\stackrel{\bf+3}{N}\stackrel{\bf -2}{O}_2 + \stackrel{\bf 0}{O}_2[/tex].
The oxidation state on two oxygen atoms in KNO₃ increases from -2 to 0. These oxygen atoms are oxidized. KNO₃ is also the reducing agent.
The oxidation state on the nitrogen atom in KNO₃ decreases from +5 to +3. That nitrogen atom is reduced. As a result, KNO₃ is also the oxidizing agent.
Reaction A
Apply these steps to reaction A.
H₂:
Oxidation state on H: 0.O₂:
Oxidation state on O: 0.H₂O:
Oxidation state on H: +1.Oxidation state on O: -2.Double check: [tex]{\bf 2} \times (+1) + (-2) = 0[/tex].[tex]\rm \stackrel{}{2}\; \stackrel{\bf 0}{H}_2 + \stackrel{\bf 0}{O}_2\stackrel{}{\to} \stackrel{}{2}\;\stackrel{\bf +1}{H}_2\stackrel{\bf -2}{O}[/tex].
The oxidation state on oxygen atoms decreases from 0 to -2. Those oxygen atoms are reduced. O₂ is thus the oxidizing agent.
The oxidation state on hydrogen atoms increases from 0 to +1. Those hydrogen atoms are oxidized. H₂ is thus the reducing agent.
In the reaction 2H₂(g) + O₂(g) → 2H₂O(l), hydrogen is oxidized and acts as the reducing agent, while oxygen is reduced and acts as the oxidizing agent. Option A is correct.
To identify which species is oxidized and which is reduced in the given reaction 2H₂(g) + O₂(g) → 2H₂O(l), we start by assigning oxidation numbers. Hydrogen is usually +1 (except in metal hydrides, where it is -1), and oxygen is usually -2 (except in peroxides, where it is -1, and in compounds with fluorine, where it is positive). In molecular hydrogen (H₂) and molecular oxygen (O₂), the oxidation numbers are 0 since they are elemental forms.
In water (H₂O), hydrogen has an oxidation number of +1 and oxygen has an oxidation number of -2. Going from 0 in H₂ to +1 in H₂O, hydrogen is oxidized (loses electrons), and going from 0 in O₂ to -2 in H₂O, oxygen is reduced (gains electrons).
Therefore, hydrogen is the reducing agent (it itself gets oxidized), and oxygen is the oxidizing agent (it itself gets reduced).
Hence, A. is the correct option.
The changing of substances to other substances by the breaking of bonds in reactants and the formation of bonds in products.
Answer:
Definition of chemical change or reaction.Explanation:
The changing of substances to other substances by the breaking of bonds in reactants and the formation of bonds in products is the definition of chemical change or reaction.
Chemical reactions or cahnges are the transformation of pure substances, compounds or elements, into other substances by the breaking of some bonds adn the formation of other bonds.
The chemical reactions are represented by chemical equations with the reactants in the left side and the products in the right side, connected by the use of arrows.
For example, the chemical equation CH₄ (g) + O₂(g) → CO₂(g) + H₂O(g) represents the combustion reaction (chemical change) of methane (CH₄) with oxygen (O₂).
The products of the reaction are carbon dioxide (CO₂) and water (H₂O) which are the new substances formed by breaking the chemical bonds in CH₄ and O₂ and the formation of the bonds in the new molecules (CO₂ and H₂O).
Chemical equation: CH₄ (g) + O₂(g) → CO₂(g) + H₂O(g)
↑ ↑ ↑ ↑
-- reactants -- --- products --
The bonds in CH₄ and O₂ are brokenThe bonds in CO₂ H₂O are formedThe reactants have been transformed into different chemical compounds, so this is a chemical changle.
Chemical reactions involve the changing of substances through the breaking and formation of bonds. Reactants are the starting substances, while products are the resulting substances. The direction of the reaction is indicated by an arrow.
Explanation:Chemical reactions occur when two or more atoms bond together to form molecules or when bonded atoms are broken apart. The substances used in a chemical reaction are called the reactants (usually found on the left side of a chemical equation), and the substances produced by the reaction are known as the products (usually found on the right side of a chemical equation). An arrow is typically drawn between the reactants and products to indicate the direction of the chemical reaction; this direction is not always a 'one-way street.'
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Which redox equation is correctly balanced?
(1) Cr3+ + Mg -> Cr + Mg2+
(2) Al3+ + K -> Al + K+
(3) Sn4+ + H2 -> Sn + 2H+
(4) Br2 + Hg -> Hg2+ + 2Br
The answer is 4), see the picture
The redox equation which is correctly balanced is: 4. [tex]Br_2 + Hg \rightarrow Hg^{2+} + 2Br[/tex]
What is a redox reaction?A redox reaction is also referred to as oxidation-reduction reaction and it can be defined as a type of chemical reaction in which the oxidation number of an atom of participating chemical species are changed.
In this scenario, the oxidation number of an atom of hydrogen is change from one to two. Thus, the redox equation which is correctly balanced is given by [tex]Br_2 + Hg \rightarrow Hg^{2+} + 2Br[/tex]
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Which equation is an example of an endothermic reaction?
Na + Br -> NaBr + Heat
H20 (s) + heat -> H2O (l)
both
neither
Answer:
H₂0[tex]_{(s)}[/tex] + heat → H₂O[tex]_{(l)}[/tex]
Explanation:
An ENDOTHERMIC reaction is a chemical reaction in which heat is absorbed by the reactants. As such the product is usually cooler than the products. In the equation above (the answer), heat is on the reactant side of the equation thus indicating that heat is absorbed by the reactants.
On the other hand, in the first equation heat is on the product side of the equation which is consistent with an Exothermic reaction.
Express this as a chemical equation: Hydrogen gas bubbled through a solution of silver nitrate?
Answer:
H₂ (g) + 2AgNO₃ (aq) → 2HNO₃ (aq) + 2Ag (s)Explanation:
1) Word equation:
Hydrogen gas + silver nitrate → nitric acid + silver2) Chemical (skeleton) equation:
Include phases but do not balance it (yet). The symbology used is:
(g) for gas(aq) for aqueous solution(s) for solidH₂ (g) + AgNO₃(aq) → HNO₃ (aq) + Ag (s)3) Balanced chemical equation:
Add the needed coefficients to make the number of atoms of each kind equal on both sides:
H₂ (g) + 2AgNO₃ (aq) → 2HNO₃ (aq) + 2Ag (s) ← answerThe chemical equation that represents hydrogen gas being bubbled through a solution of silver nitrate is: 2AgNO3(aq) + H2(g) -> 2Ag(s) + 2HNO3(aq). This is a redox reaction where silver is reduced and hydrogen is oxidized.
Explanation:When hydrogen gas is bubbled through a solution of silver nitrate, a chemical reaction occurs. This can be written as a chemical equation:
2AgNO3(aq) + H2(g) -> 2Ag(s) + 2HNO3(aq)
In this equation, hydrogen gas (H2) reacts with silver nitrate (AgNO3) in the solution to form solid silver (Ag) and nitric acid (HNO3). This is a redox reaction, where silver is reduced (gains electrons) and hydrogen is oxidized (loses electrons).
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What amounts do you compare when measuring concentration
Answer:
When measuring concentration you compare the amount of solute to the amount of solvent or solution.Explanation:
The concentration is a measure of how much solute is present in certain amount of solvent or solution. There are many quantitative expressions for the concentration. Some of those expressions are: percentage, molarity, molality, molar fraction, among others.
This table shows the expressions for some concentration measures, showing the amounts compared.
Concentration amounts compared in form of ratio
Percentage, mass/mass (mass of solute / mass of solution) × 100
Percentage, vol./vol. (vol. of solue / vol. of solution) × 100
Molarity (moles of solute / liters of solution)
Molality (moles of solute / Kg of solvent)
A sodium atom has an electron configuration of 1s22s22p63s1.if the sodium atom becomes ionized, its new electron configuration will be the same as which element? select one:a. neonb. magnesiumc. lithiumd. potassium
Answer:
Neon
Explanation:
1s² 2s² 2p⁶ 3s¹ or [Ne] 3s¹
The outer most shell is the 3s¹.
For this atom to achieve stability, if it loses the electron in the 3s shell, it would resemble an inert element with a complete octet configuration. Therefore, the atom would be like:
1s² 2s² 2p⁶ which is the configuration of Ne
What volume of a 2.0M NaOH solution would be lethal for a 60kg person?
(LD50 NaOH = 0.0010 mol/kg)
Answer:
[tex]\boxed{\text{30 mL}}[/tex]
Explanation:
Step 1. Calculate the moles of NaOH
[tex]n = \text{60.0 kg} \times \dfrac{\text{0.0010 mol}}{\text{1 kg}} = \text{0.0600 mol}[/tex]
Step 2. Calculate the volume of NaOH
[tex]V = \text{0.0600 mol} \times \dfrac{\text{1 L}}{\text{2.0 mol}} = \text{0.030 L} = \text{30 mL}\\\\\text{The lethal volume of NaOH is } \boxed{\textbf{30 mL}}[/tex]
Final answer:
To find the lethal volume of a 2.0M NaOH solution for a 60kg person, calculate the total lethal dose (0.060 mol) and then divide by the concentration (2.0M), resulting in 30 mL.
Explanation:
The question involves calculating the lethal volume of a 2.0M NaOH solution for a 60kg person based on the lethal dose (LD50) of NaOH, which is 0.0010 mol/kg. First, we need to determine the total lethal dose of NaOH for the person:
Total lethal dose = LD50 * Body weight = 0.0010 mol/kg * 60 kg = 0.060 mol.To find the volume of the 2.0M NaOH solution needed to reach this lethal dose, we use the formula: Volume = moles of solute/concentration of solution.Volume = 0.060 mol / 2.0 M = 0.030 L or 30 mL.Therefore, the lethal volume of a 2.0M NaOH solution for a 60kg person is 30 mL.
Practice 11: Balance this redox reaction using the oxidation-number change method and describe each step you used:
HCl (aq) + Zn (s) → ZnCl2 (s) + H2 (g)
Answer:
2 HCl(aq) + Zn(s) = ZnCl2(s) + H2(g)
Single Replacement Reaction
Which one goes where? Thanks!
It's in a file. ⬇
1 -> theory
2-> law
3-> hypothesis
In order to synthesize proteins, carbohydrates, lipids, and nucleic acids, cells require _____.
disaccharides
energy
an adenosine group
a sugar group
Answer:
Energy
Explanation:
A sugar group would be used for carbohydrates or nucleic acids. An adenosine group would be used in ATP formation if I recall correct. And disaccharides are just two monosaccharides linked together, so that would also be for carbohydrates. Therefore, energy is the answer.
In a chemical equation the arrow (indicating a reaction) points in which direction
Calculate the pressure in atmospheres of 0.5 mol of Helium ( He) at 20°C & occupying 2.50 L.
Answer:
4.811 atm.
Explanation:
We can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm (P = ?? atm).
V is the volume of the gas in L (V = 2.5 L).
n is the no. of moles of the gas in mol (n = 0.5 mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K),
T is the temperature of the gas in K (T = 20°C + 273 = 293 K).
∴ P = nRT/V = (0.5 mol)(0.0821 L.atm/mol.K)(293 K)/(2.5 L) = 4.811 atm.
in which of the following is the solution concentration expressed in percent by volume
10 mL of solute
_________ x 100%
100 ml of solvent
10 g of solute
_________ x 100%
100 ml of solvent
10 mL of solute
_________ x 100%
100 ml of solution
10 g of solute
_________ x 100%
100 ml of solution
Answer : The correct option is, [tex]\frac{10g\text{ of solute}}{100ml\text{ of solution}}\times 100\%[/tex]
Explanation :
The solution concentration expressed in percent by volume means that the amount of solute present in 100 parts volume of solution.
It is represented in formula as :
[tex]\text{Percent solution by volume}=\frac{\text{Amount of solute}}{\text{Amount of solution}}\times 100\%[/tex]
Or,
[tex]\text{Percent solution by volume}=\frac{10g\text{ of solute}}{100ml\text{ of solution}}\times 100\%[/tex]
Hence, the correct option is, [tex]\frac{10g\text{ of solute}}{100ml\text{ of solution}}\times 100\%[/tex]