Kimberly Lopez
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Physics

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Kimberly Lopez
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Exam 3

Pregunta 1 de 92

1

What is the activation energy?

Selecciona una de las siguientes respuestas posibles:

  • the energy difference between the reactants and the products

  • the amount of energy required to activate a phase change

  • the amount of energy required to separate reactants from the products

  • the minimum amount of energy in order to transform into product molecules

  • the hill

Explicación

Pregunta 2 de 92

1

Why might increasing the concentration of a set of reactants increase the rate of reaction?

Selecciona una de las siguientes respuestas posibles:

  • You have increased the ratio of reactants to products.

  • The rate of reaction depends only on the mass of the atoms and therefore increases as you increase the mass of the reactants.

  • The concentration of reactants is unrelated to the rate of reaction.

  • You have increased the chances that any two reactant molecules will collide and react.

  • none of the above

Explicación

Pregunta 3 de 92

1

What is the formula mass of a molecule of C6H12O6?

Selecciona una de las siguientes respuestas posibles:

  • 180 amu

  • 24 amu

  • 168 amu

  • 29 amu

  • none of the above

Explicación

Pregunta 4 de 92

1

If it takes 200 golf balls to equal the mass of four bowling balls, what is the relative mass of bowling balls to golf balls?

Selecciona una de las siguientes respuestas posibles:

  • 20 times

  • 1/20

  • 100 times

  • 6.022 × 1023

  • 1/50

Explicación

Pregunta 5 de 92

1

Given the following generic chemical reaction, which is the product?

X → Y

Selecciona una de las siguientes respuestas posibles:

  • → is the product.

  • X is the product.

  • Y is the product.

  • Both X and Y are the products.

  • Both X and Y are the reactants.

Explicación

Pregunta 6 de 92

1

Which of the following reaction energies is the most endothermic?

Selecciona una de las siguientes respuestas posibles:

  • -540 kJ/mole

  • 540 kJ/mole

  • 125 kj/mole

  • -125 kJ/mole

  • not enough information given

Explicación

Pregunta 7 de 92

1

Use the bond energies below to determine whether the following reaction is exothermic or endothermic:

H2 + Cl2 → 2 HCl

H-H (bond energy: 436 kJ/mol)
Cl-Cl (bond energy: 243 kJ/mol)
H-Cl (bond energy: 431 kJ/mol)

Selecciona una de las siguientes respuestas posibles:

  • Exothermic with more than 50 kJ of energy released.

  • Endothermic with more than 50 kJ of energy absorbed.

  • Endothermic with less than 50 kJ of energy absorbed.

  • Exothermic with less than 50 kJ of energy released.

Explicación

Pregunta 8 de 92

1

What is an exothermic reaction?

Selecciona una de las siguientes respuestas posibles:

  • It is a reaction where there is a net adsorption of energy from a reaction.

  • It is a reaction where the products have more energy than the reactants.

  • It is a reaction that requires heat as a reactant.

  • all of the above

  • none of the above

Explicación

Pregunta 9 de 92

1

Which of the following is a correctly balanced equation?

Selecciona una de las siguientes respuestas posibles:

  • 2 P4 + 12 H2 → 8 PH3

  • 0 P4 + 6 H2 → 4 PH3

  • P4 + 3 H2 → PH3

  • P4 + 6 H2 → 4 PH3

  • 1 P4 + 6 H2 → 4 PH3

Explicación

Pregunta 10 de 92

1

For the following balanced reaction, which of the following is a solid?

2 Na(l) + Cl2(g) → 2 NaCl(s)

Selecciona una de las siguientes respuestas posibles:

  • NaCl

  • Cl

  • Na

  • Cl2

  • 2 Na

Explicación

Pregunta 11 de 92

1

What is the mass of an oxygen atom, O, in atomic mass units?

Selecciona una de las siguientes respuestas posibles:

  • 16 amu

  • 12 amu

  • 18 amu

  • 32 amu

Explicación

Pregunta 12 de 92

1

How does a catalyst increase the rate of a reaction?

Selecciona una de las siguientes respuestas posibles:

  • It increases the energy difference between the reactants and products.

  • It is neither created nor consumed in a reaction.

  • It raises the activation energy of the reactants, which makes the reaction proceed faster.

  • It has nothing to do with the rate of reaction.

  • It lowers the activation energy.

Explicación

Pregunta 13 de 92

1

Which of the following statements best describes the concept of entropy?

Selecciona una de las siguientes respuestas posibles:

  • Energy has a tendency to remain in one place.

  • The energy released in a chemical reaction is the same as the difference in the energy of the bonds broken and formed.

  • The entropy of the universe is constantly decreasing.

  • Energy has a tendency to disperse.

  • Energy is neither created nor destroyed.

Explicación

Pregunta 14 de 92

1

For the following balanced reaction, which of the following is a gas?

2 Na(l) + Cl2(g) → 2 NaCl(s)

Selecciona una de las siguientes respuestas posibles:

  • 2 Na

  • Na

  • Cl

  • NaCl

  • Cl2

Explicación

Pregunta 15 de 92

1

If it takes energy to break bonds and you gain energy in the formation of bonds, how can some reactions be exothermic while others are endothermic?

Selecciona una de las siguientes respuestas posibles:

  • Some products have more energy than others and they always require energy to be formed.

  • Some reactants have more energetic bonds than others and they will always release energy.

  • It is the total amount of energy that matters. Sometimes some bonds are stronger than others and so you gain or lose energy when you form them.

  • It is the total number of bonds that matters. Sometimes you create more bonds than you break and since all bonds have same amount of energy you gain or lose energy depending on the number of bonds.

  • none of the above

Explicación

Pregunta 16 de 92

1

Given the following generic chemical reaction, which is the reactant?

X → Y

Selecciona una de las siguientes respuestas posibles:

  • → is the reactant.

  • X is the reactant.

  • Y is the reactant.

  • Both X and Y are the products.

  • Both X and Y are the reactants.

Explicación

Pregunta 17 de 92

1

What is a chemical reaction?

Selecciona una de las siguientes respuestas posibles:

  • when two solids mix together to form a heterogeneous mixture

  • when two liquids mix to form a homogeneous mixture

  • when a liquid undergoes a phase change and produces a solid

  • when one or more new compounds are formed by rearranging atoms

  • when a new element is formed by rearranging nucleons

Explicación

Pregunta 18 de 92

1

Which is higher in an endothermic reaction: the potential energy of the reactants or the potential energy of the products?

Selecciona una de las siguientes respuestas posibles:

  • The potential energy of the reactants is higher than the potential energy of the products.

  • The potential energy of the products is higher than the potential energy of the reactants.

  • In the early stages of the reaction the potential energy of the reactants is higher. In the later stages, the potential energy of the products is higher.

  • The potential energy of the reactants is the same as the potential energy of the products.

Explicación

Pregunta 19 de 92

1

What are the formula masses of water, H2O; propene, C3H6; and 2-propanol, C3H8O?

Selecciona una de las siguientes respuestas posibles:

  • water: 18 amu; propene: 44 amu; 2-propanol: 64 amu

  • water: 18 amu; propene: 40 amu; 2-propanol: 58 amu

  • water: 18 amu; propene: 42 amu; 2-propanol: 60 amu

  • water: 18 amu; propene: 42 amu; 2-propanol: 62 amu

Explicación

Pregunta 20 de 92

1

What is a reaction rate?

Selecciona una de las siguientes respuestas posibles:

  • It is the speed with which products form from the reactants

  • It is the ratio of the molecular masses of the elements in a given compound.

  • It is the balanced chemical formula that relates the number of product molecules to reactant molecules.

  • It is the ratio of the masses of products and reactants.

  • none of the above

Explicación

Pregunta 21 de 92

1

What is the mass of a water molecule, H2O, in atomic mass units?

Selecciona una de las siguientes respuestas posibles:

  • 3 amu

  • 18 amu

  • 2 amu

  • 16 amu

Explicación

Pregunta 22 de 92

1

According to the following balanced chemical equation, if you want to generate two moles of H2O, how many moles of O2 do you need?

2 H2 + O2 → 2 H2O

Selecciona una de las siguientes respuestas posibles:

  • 2

  • 1

  • 6.022 × 1023

  • 1/2

  • 4

Explicación

Pregunta 23 de 92

1

Why is it important for a chemist to know the relative masses of atoms?

Selecciona una de las siguientes respuestas posibles:

  • There are not that many different kinds of atoms and so it's important to know how they relate to one another.

  • It provides information about how many atoms two samples have relative to each other

  • Because the mass of an atom is directly related to its chemical properties.

  • It provides an indication of how the different atoms will interact

Explicación

Pregunta 24 de 92

1

What is an endothermic reaction?

Selecciona una de las siguientes respuestas posibles:

  • It is a reaction that requires heat as a reactant.

  • It is a reaction where there is a net adsorption of energy from a reaction.

  • It is a reaction where the products have more energy than the reactant

  • all of the above

  • none of the above

Explicación

Pregunta 25 de 92

1

For the following balanced equation, which has the highest coefficient?

4 H2 + 2 C → 2 CH4

Selecciona una de las siguientes respuestas posibles:

  • H2

  • H4

  • CH4

  • C

  • none of the above

Explicación

Pregunta 26 de 92

1

Which of the following materials is most likely to undergo reduction?

Selecciona una de las siguientes respuestas posibles:

  • Cl-

  • Na+

  • Cl2

  • Na

  • both A and B

Explicación

Pregunta 27 de 92

1

For the following acid-base reaction, identify what compound is formed in the space marked.

HNO3 + KOH ⇌ ???? + H2O

Selecciona una de las siguientes respuestas posibles:

  • KNO3

  • KOH2

  • H3ONO3

  • KOH2NO3

  • none of the above

Explicación

Pregunta 28 de 92

1

For each of the following unbalanced equations, which is depicted: oxidation or reduction?

a) Cr → Cr3+ b) Sn → Sn(OH)42-

Selecciona una de las siguientes respuestas posibles:

  • a) reduction; b) oxidation

  • a) reduction; b) reduction

  • a) oxidation; b) reduction

  • a) oxidation; b) oxidation

Explicación

Pregunta 29 de 92

1

Which of the following solutions is the most acidic?

Selecciona una de las siguientes respuestas posibles:

  • a solution with a pH = 10

  • a solution with a pH = 14

  • a solution with a pH = 7

  • a solution with a pH = 4

  • All of the solutions are basic.

Explicación

Pregunta 30 de 92

1

Which of the following statements describes a basic solution?

Selecciona una de las siguientes respuestas posibles:

  • [H3O+] [OH-]

  • [H3O+] × [OH-] ≠ 1 × 10-14

  • [H3O+]/[OH-] = 1

  • [H3O+] > [OH-]

  • [H3O+]/[OH-] = 1 × 10-14

Explicación

Pregunta 31 de 92

1

What is a base?

Selecciona una de las siguientes respuestas posibles:

  • Anything with a bitter taste.

  • Anything that can be used to clean drains.

  • Anything that accepts a hydroxide ion.

  • Anything that accepts a hydrogen ion.

  • Anything that donates a hydroxide ion.

Explicación

Pregunta 32 de 92

1

For the following reaction, identify whether the compound in bold is behaving as an acid or a base.

H3PO4 + H2O ⇌ H2PO4- + H3O+

Selecciona una de las siguientes respuestas posibles:

  • acid

  • base

  • neither

  • both

  • none of the above

Explicación

Pregunta 33 de 92

1

For the following reaction, identify whether the compound in bold is behaving as an acid or a base.

H3PO4 + H2O ⇌ H2PO4- + H3O+

Selecciona una de las siguientes respuestas posibles:

  • acid

  • base

  • neither

  • both

  • none of the above

Explicación

Pregunta 34 de 92

1

According to the following reaction, which molecule is acting as an acid?

H3O+ + HSO4- → H2O + H2SO4

Selecciona una de las siguientes respuestas posibles:

  • H2SO4

  • HSO4-

  • H2O

  • H3O+

  • none of the above

Explicación

Pregunta 35 de 92

1

What is an acid?

Selecciona una de las siguientes respuestas posibles:

  • Anything that accepts hydrogen atoms.

  • Anything that donates hydrogen atoms.

  • Anything that donates hydrogen ions.

  • Anything that dissolves metal.

  • Anything that donates hydronium ions.

Explicación

Pregunta 36 de 92

1

How many electrons are gained or lost in the following half-reaction?

Na → Na+

Selecciona una de las siguientes respuestas posibles:

  • 1/2 electron is gained

  • 2 electrons are gained

  • 1 electron is lost

  • 1/2 electron is lost

  • 1 electron is gained

Explicación

Pregunta 37 de 92

1

What is a reduction?

Selecciona una de las siguientes respuestas posibles:

  • the formation of red compounds in the presence of an oxidant

  • the gain of electrons

  • the reaction of oxygen with a reductant

  • the loss of an electron from the valence shell

  • the reduction of the number of electrons

Explicación

Pregunta 38 de 92

1

What is oxidation?

Selecciona una de las siguientes respuestas posibles:

  • the reduction of oxygen

  • the loss of electrons

  • the addition of an electron to the valence shell

  • the gaining of electrons

  • the reaction with oxygen

Explicación

Pregunta 39 de 92

1

How is electrolysis different from what is going on chemically inside a battery?

Selecciona una de las siguientes respuestas posibles:

  • You cannot make pure compounds with electrolysis.

  • Electrolysis does not use electrons.

  • You do not produce a chemical change in electrolysis.

  • They are the same process, just reversed.

  • Electrolysis only uses electrons from a cathode.

Explicación

Pregunta 40 de 92

1

An acid and a base react to form a salt, which consists of positive and negative ions. Which forms the positive ions: the acid or the base? Which forms the negative ions?

Selecciona una de las siguientes respuestas posibles:

  • The acid forms the negative ion, the base forms the positive ion.

  • The acid forms the positive ion, the base forms the negative ion.

  • Because different substances can act as an acid or a base, it depends on the substance you begin with.

  • all of the above

Explicación

Pregunta 41 de 92

1

According to the following reaction, which molecule is acting as a base?

H3O+ + HSO4- → H2O + H2SO4

Selecciona una de las siguientes respuestas posibles:

  • H2O

  • HSO4-

  • H2SO4

  • H3O+

  • none of the above

Explicación

Pregunta 42 de 92

1

For the following reaction, identify whether the compound in bold is behaving as an acid or a base.

H3PO4 + H2O ⇌ H2PO4- + H3O+

Selecciona una de las siguientes respuestas posibles:

  • acid

  • base

  • neither

  • both

  • none of the above

Explicación

Pregunta 43 de 92

1

Which of the following statements is not true about a neutralization reaction?

Selecciona una de las siguientes respuestas posibles:

  • One molecule of acid neutralizes one molecule of base.

  • A neutralization is the reaction of a hydroxide ion with a proton.

  • Water is always formed in a neutralization reaction.

  • All of the above are true.

  • None of the above are true.

Explicación

Pregunta 44 de 92

1

Which of the following statements describes a neutral solution?

Selecciona una de las siguientes respuestas posibles:

  • [H3O+] > [OH-]

  • [H3O+] × [OH-] ≠ 1 × 10-14

  • [H3O+]/[OH-] = 1 × 10-14

  • [H3O+] [OH-]

  • [H3O+]/[OH-] = 1

Explicación

Pregunta 45 de 92

1

How many electrons are gained or lost in the following half-reaction?

Cl2 → 2 Cl-

Selecciona una de las siguientes respuestas posibles:

  • 4 electrons are gained

  • 2 electrons are lost

  • 1/2 electron is lost

  • 2 electrons are gained

  • 1/2 electron is gained

Explicación

Pregunta 46 de 92

1

According to the following reaction, which molecule is acting as a base?

H2O + NH3 → OH- + NH4+

Selecciona una de las siguientes respuestas posibles:

  • H2O

  • NH4+

  • OH-

  • NH3

  • none of the above

Explicación

Pregunta 47 de 92

1

Which of the following statements about electrochemistry is not true?

Selecciona una de las siguientes respuestas posibles:

  • It involves the use of a set of oxidation-reduction reactions to produce electrical current.

  • It is the study of how electrical energy and chemical reactions are related.

  • It involves the use of electrical current to produce an oxidation-reduction reaction.

  • It is the study of how electrons are transferred from one chemical compound to another.

  • All of the above are true.

Explicación

Pregunta 48 de 92

1

What element is oxidized in the following equation and what element is reduced?

Sn2+ + 2 Ag → Sn + 2 Ag⁺

Selecciona una de las siguientes respuestas posibles:

  • The tin ion, Sn2+, is oxidized, while the silver, Ag, is reduced.

  • Both the tin ion, Sn2+, and the silver, Ag, are reduced.

  • Both the tin ion, Sn2+, and the silver, Ag, are oxidized.

  • The tin ion, Sn2+, is reduced, while the silver, Ag, is oxidized.

Explicación

Pregunta 49 de 92

1

According to the following reaction, which molecule is acting as a base?

OH- + NH4+ → H2O + NH3

Selecciona una de las siguientes respuestas posibles:

  • OH-

  • NH3

  • NH4+

  • H2O

  • none of the above

Explicación

Pregunta 50 de 92

1

For the following acid-base reaction, identify what compound is formed in the space marked.

HCl + KOH ⇌ ???? + H2O

Selecciona una de las siguientes respuestas posibles:

  • H3OCl

  • KOH2Cl

  • KCl

  • KOH2

  • none of the above

Explicación

Pregunta 51 de 92

1

What is the activation energy?

Selecciona una de las siguientes respuestas posibles:

  • the energy difference between the reactants and the products

  • the amount of energy required to activate a phase change

  • the amount of energy required to separate reactants from the products

  • the minimum amount of energy in order to transform into product molecules

  • the hill

Explicación

Pregunta 52 de 92

1

Is it possible to have a macroscopic sample of oxygen that has a mass of 14 atomic mass units?

Selecciona una de las siguientes respuestas posibles:

  • No, because oxygen is a gas at room temperature.

  • Yes, but it would have the same density as nitrogen.

  • No, this is less than than the mass of a single oxygen atom.

  • Yes, but it would need to be made of oxygen atoms that each had less than the normal number of neutrons.

Explicación

Pregunta 53 de 92

1

Why might increasing the temperature alter the rate of a chemical reaction?

Selecciona una de las siguientes respuestas posibles:

  • The molecules will have a higher kinetic energy and bump into one another harder.

  • The density decreases as a function of temperature and this leads to an increase in volume which drops the rate of reaction.

  • The molecules are less reactive at higher temperatures.

  • The molecules will more likely combine with other atoms at high temperature to save space.

  • none of the above

Explicación

Pregunta 54 de 92

1

A refrigerator delays the spoilage of food by

Selecciona una de las siguientes respuestas posibles:

  • diminishing the supply of oxygen to microorganism

  • slowing down the rate of chemical reactions within microorganisms.

  • expanding the water found within microorganisms.

  • killing microorganisms.

Explicación

Pregunta 55 de 92

1

The ________ is what needs to be overcome in a reaction so that it can proceed to the products.

Selecciona una de las siguientes respuestas posibles:

  • catalyst

  • thermodynamics

  • bond energy

  • activation energy

  • entropy

Explicación

Pregunta 56 de 92

1

Which of the following statements about catalysts is NOT true?

Selecciona una de las siguientes respuestas posibles:

  • A catalyst does not change the energy of the reactants or the products.

  • A catalyst can be used to speed up slow reactions.

  • A catalyst alters the rate of a chemical reaction.

  • A catalyst can be consumed in a reaction as long as it is regenerated.

  • All of the above are true.

Explicación

Pregunta 57 de 92

1

What is the formula mass of sulfur dioxide, SO2?

Selecciona una de las siguientes respuestas posibles:

  • about 32 amu

  • about 60 amu

  • about 16 amu

  • about 64 amu

Explicación

Pregunta 58 de 92

1

What coefficient is needed in front of the O2 molecule to balance the following equation?

2 C4H10 (g) + _____ O2 (g) → 8CO2 (g) + 10 H2O (l)

Selecciona una de las siguientes respuestas posibles:

  • 5

  • 1

  • 13

  • 8

Explicación

Pregunta 59 de 92

1

How is Avogadro's number related to the numbers on the periodic table?

Selecciona una de las siguientes respuestas posibles:

  • The periodic table tells you the mass of one atom. From that, and Avogadro's number you know the number of moles.

  • The mass listed is Avogadro's number.

  • The masses are all divisible by Avogadro's number, which gives you the weight of one mole.

  • The periodic table only gives us atomic numbers, not atomic mass.

  • The atomic mass listed is the mass of Avogadro's number's worth of atoms.

Explicación

Pregunta 60 de 92

1

What is wrong with the following depiction of a chemical reaction?

Selecciona una de las siguientes respuestas posibles:

  • One box contains more atoms than the other.

  • One box contains more molecules than the other.

  • These boxes contain only molecules but no atoms.

  • All of the above.

Explicación

Pregunta 61 de 92

1

What is the mass of one mole of H2?

Selecciona una de las siguientes respuestas posibles:

  • 6.022 × 1023 g

  • 1 g

  • 20 g

  • 2 g

  • none of the above

Explicación

Pregunta 62 de 92

1

Why is heat often added to chemical reactions performed in the laboratory?

Selecciona una de las siguientes respuestas posibles:

  • to increase the rate at which reactant collide

  • to compensate for the natural tendency of energy to disperse

  • to allow a greater number of reactants to pass over the activation energy

  • all of the above

Explicación

Pregunta 63 de 92

1

Which equations are balanced?
a) Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)
b) 3Al (s) + 3 Br2 (l) → Al2Br3 (s)
c) 2HgO (s) → 2 Hg (l) + O2 (g)

Selecciona una de las siguientes respuestas posibles:

  • Only equation "c" is balanced.

  • Equations "b" and "c" are balanced.

  • Equations "a" and "c" are balanced.

  • All of them are balanced.

Explicación

Pregunta 64 de 92

1

According to the following balanced chemical equation, if you want to generate two moles of H2O how many grams of O2 do you need?

2 H2 + O2 → 2 H2O

Selecciona una de las siguientes respuestas posibles:

  • 32

  • 4

  • 8

  • 16

  • 6.022 × 1023

Explicación

Pregunta 65 de 92

1

How does formula mass differ from atomic mass?

Selecciona una de las siguientes respuestas posibles:

  • The atomic mass of a substance is the sum of the formula masses of the elements is its chemical formula. The atomic mass is the mass of a single atom.

  • The formula mass is the mass of the chemical formula and the atomic mass is the mass of the molecule.

  • They represent the same thing.

  • The formula mass of a substance is the sum of the atomic masses of the elements is its chemical formula. The atomic mass is the mass of a single atom.

Explicación

Pregunta 66 de 92

1

Which of the following has the greatest number of particles?

Selecciona una de las siguientes respuestas posibles:

  • 1 mole of Be

  • 1 mole of Na

  • 9.012 g of Be

  • 22.990 g of Na

  • All are the same.

Explicación

Pregunta 67 de 92

1

For the following reaction, identify whether the compound in bold is behaving as an acid or a base.

H3PO4 + H2O ⇌ H2PO4- + H3O+

Selecciona una de las siguientes respuestas posibles:

  • acid

  • base

  • neither

  • both

  • none of the above

Explicación

Pregunta 68 de 92

1

Which of the following statements describes an acidic solution?

Selecciona una de las siguientes respuestas posibles:

  • [H3O+]/[OH-] = 1

  • [H3O+] > [OH-]

  • [H3O+]/[OH-] = 1 × 10-14

  • [H3O+] [OH-]

  • [H3O+] × [OH-] ≠ 1 × 10-14

Explicación

Pregunta 69 de 92

1

How many electrons are gained or lost in the following half-reaction?

2 Na → 2 Na+

Selecciona una de las siguientes respuestas posibles:

  • 4 electrons are gained

  • 1/2 electron is lost

  • 1/2 electron is gained

  • 2 electrons are lost

  • 2 electrons are gained

Explicación

Pregunta 70 de 92

1

Which of the following statements is untrue about oxidation and reduction processes?

Selecciona una de las siguientes respuestas posibles:

  • Often ions are generated or consumed.

  • An oxidation can happen without a reduction.

  • It involves the exchange of electrons.

  • Electrons are often involved in oxidation and reduction reactions.

  • All of the above are true.

Explicación

Pregunta 71 de 92

1

Which of the following statements about oxidation and reduction reactions is true?

Selecciona una de las siguientes respuestas posibles:

  • Only neutral atoms are formed in oxidation and reduction reactions.

  • More than one electron can be transferred in an oxidation and reduction reaction.

  • A half-reaction is only used for reduction reactions.

  • In a half-reaction, only half of an electron is transferred.

  • None of the above are true.

Explicación

Pregunta 72 de 92

1

How many electrons are gained or lost in the following half-reaction?

Zn → Zn+2

Selecciona una de las siguientes respuestas posibles:

  • 2 electrons are lost

  • 1/2 electron is gained

  • 4 electrons are gained

  • 2 electrons are gained

  • 1/2 electron is lost

Explicación

Pregunta 73 de 92

1

According to the following reaction, which molecule is acting as an acid?

OH- + NH4+ → H2O + NH3

Selecciona una de las siguientes respuestas posibles:

  • H2O

  • OH-

  • NH4+

  • NH3

  • none of the above

Explicación

Pregunta 74 de 92

1

Which of the following compounds would least likely act as an acid?

Selecciona una de las siguientes respuestas posibles:

  • HSO4-1

  • SO4-2

  • H2SO4

  • CH3CO2H

  • NH3

Explicación

Pregunta 75 de 92

1

In the reaction below, what does the symbol ⇌ mean?

OH- + NH4+ ⇌ H2O + NH3

Selecciona una de las siguientes respuestas posibles:

  • It means that the backward reaction happens as fast as the forward reaction and so the proton is not transferred at all.

  • It means that the forward and backward reactions are happening at the same time.

  • It means that the forward reaction does not progress.

  • It means that the reaction cannot decide which way to go.

  • none of the above

Explicación

Pregunta 76 de 92

1

According to the following reaction, which molecule is acting as an acid?

H2O + NH3 → OH- + NH4+

Selecciona una de las siguientes respuestas posibles:

  • NH4+

  • H2O

  • NH3

  • OH-

  • none of the above

Explicación

Pregunta 77 de 92

1

Qualitatively, what happens to the hydroxide ion concentration if you decrease the hydronium ion concentration?

Selecciona una de las siguientes respuestas posibles:

  • The concentration of OH- increases.

  • The concentration of OH- stays the same but the ratio OH-/H3O+ changes.

  • The concentration of OH- increases but the ratio stays the same.

  • none of the above

Explicación

Pregunta 78 de 92

1

How do you make a proton out of a hydrogen atom?

Selecciona una de las siguientes respuestas posibles:

  • remove a proton from a helium nucleus

  • let the hydrogen atoms undergo fusion

  • let the hydrogen atoms combine to form a hydrogen molecule and eject a proton

  • remove an electron from a hydrogen atom

  • let the hydrogen atoms combine to form a hydrogen molecule and eject an electron

Explicación

Pregunta 79 de 92

1

What is the formula mass of a molecule of CO2?

Selecciona una de las siguientes respuestas posibles:

  • 118 amu

  • 56 amu

  • 44 amu

  • 58.9 amu

  • none of the above

Explicación

Pregunta 80 de 92

1

Some reactions are more sluggish than others. To speed up these reactions and save energy a(n) ________ is sometimes added.

Selecciona una de las siguientes respuestas posibles:

  • heat source

  • activator

  • reaction profile

  • catalyst

  • exotherm

Explicación

Pregunta 81 de 92

1

Given the following generic chemical reaction, which is the product?

X → Y

Selecciona una de las siguientes respuestas posibles:

  • → is the product.

  • X is the product.

  • Y is the product.

  • Both X and Y are the products.

  • Both X and Y are the reactants.

Explicación

Pregunta 82 de 92

1

Which of the following reaction energies is the least exothermic (but still an exothermic reaction)?

Selecciona una de las siguientes respuestas posibles:

  • -125 kJ/mole

  • 540 kJ/mole

  • 125 kJ/mole

  • -540 kJ/mole

  • not enough information given

Explicación

Pregunta 83 de 92

1

What is a chemical equation?

Selecciona una de las siguientes respuestas posibles:

  • It is the sum of the masses of the products and reactants.

  • It is any type of reaction that takes place at the equator.

  • It is a picture of the atoms undergoing a chemical equalization.

  • It is the chemical combination of equal numbers of reactants and products.

  • It is a shorthand notation for illustrating a chemical reaction.

Explicación

Pregunta 84 de 92

1

Balance the following equation.
____ NO → ____ N2O + _____ NO2

Selecciona una de las siguientes respuestas posibles:

  • 3, 0, 0

  • 1, 2, 4

  • 3, 1, 1

  • 4, 4, 8

  • 6, 2, 1

Explicación

Pregunta 85 de 92

1

According to the following balanced chemical equation, if you want to generate two moles of H2O , how many molecules of O2 do you need?

2 H2 + O2 → 2 H2O

Selecciona una de las siguientes respuestas posibles:

  • 2

  • 1

  • 1/2

  • 4

  • 6.022 × 10^23

Explicación

Pregunta 86 de 92

1

According to the following reaction, which molecule is acting as an acid?

H2O + NH3 → OH- + NH4+

Selecciona una de las siguientes respuestas posibles:

  • NH4+

  • H2O

  • NH3

  • OH-

  • none of the above

Explicación

Pregunta 87 de 92

1

Which of the following solutions is the most acidic?

Selecciona una de las siguientes respuestas posibles:

  • a solution with a pH = 7

  • a solution with a pH = 14

  • a solution with a pH = 13

  • a solution with a pH = 12

  • All of the solutions are basic.

Explicación

Pregunta 88 de 92

1

How many electrons are gained or lost in the following half-reaction?

Cl2 → 2 Cl-

Selecciona una de las siguientes respuestas posibles:

  • 4 electrons are gained

  • 2 electrons are lost

  • 1/2 electron is lost

  • 2 electrons are gained

  • 1/2 electron is gained

Explicación

Pregunta 89 de 92

1

For the following acid-base reaction, identify what is formed in the space marked.

HF + KOH ⇌ ???? + H2O

Selecciona una de las siguientes respuestas posibles:

  • H3OF

  • KOH2

  • KF

  • KOH2F

  • none of the above

Explicación

Pregunta 90 de 92

1

As the pH increases, the hydroxide ion concentration ________.

Selecciona una de las siguientes respuestas posibles:

  • gets larger

  • goes down

  • stays constant

  • starts to decrease because it is reacting with the excess hydronium ions

  • starts to affect the H+ concentration

Explicación

Pregunta 91 de 92

1

According to the following reaction, which molecule is acting as an acid?

H2O + H2SO4 → H3O+ + HSO4-

Selecciona una de las siguientes respuestas posibles:

  • H3O+

  • H2SO4

  • H2O

  • HSO4-

  • none of the above

Explicación

Pregunta 92 de 92

1

According to the following reaction, which molecule is acting as a base?

H3O+ + HSO4- → H2O + H2SO4

Selecciona una de las siguientes respuestas posibles:

  • H2O

  • HSO4-

  • H2SO4

  • H3O+

  • none of the above

Explicación