Question 37 Which of the following is not a step in balancing redox reactions in acidic solution, using the half-reaction method?

Question 37

Which of the following is not a step in balancing redox reactions in acidic solution, using the half-reaction method?

H2O and OH- are added as needed to the half-reaction equations to make the number of oxygen and hydrogen atoms balance.

Divide the chemical equation into two half-reaction equations, identifying which half-reaction is oxidation and which is reduction.

H2O and H+ are added as needed to the half-reaction equations to make the number of oxygen and hydrogen atoms balance.

Multiply each term in one of the half-reaction equations by a factor that will make the number of electrons lost (in the oxidation) equal to the number of electrons gained (in the reduction).

38.Consider the following unbalanced redox reaction: MnO4- (aq) + SbH3 (aq) → MnO2 (s) + Sb (s)

What is the reducing agent?

MnO4-

SbH3

MnO2

Sb

Question 39

Consider the following unbalanced redox reaction:

What is the oxidizing agent in the reaction?

Cr2O72-

NO2-

Cr3+

NO3-

Some type of path is necessary to join both half-cells in order for electron flow to occur.

TRUE

FALSE

Question 42

What is the source of the electric current produced by a voltaic cell?

a spontaneous oxidation-reduction reaction

competing salt bridges

non-spontaneous reduction at the cathode

an imbalance of ion charges

Question 43

In general, breaking bonds results in a release of energy.

TRUE

FALSE

Question 44

A particular chemical reaction releases energy. It is possible to say the reactants had a higher energy than the products.

TRUE

FALSE

Question 45

When heat is applied to a solid and a gas begins to form, the change in entropy is positive.

TRUE

FALSE

Question 46

Which of the following is an example of +ΔS?

A solid being sublimed

A gas being condensed to form a liquid

A liquid freezing into a solid

A gas being compressed at low temperature to a solid

Question 47

A reaction contains two reactants, A and B. If A is doubled, there will be a greater number of effective collisions between reactants.

TRUE

FALSE

Question 48

You can study reaction rates to answer which of the following questions?

Will the reaction be reversible?

Will the reaction occur?

How can the reaction be slowed down?

How many grams of product will be formed?

Question 49

Which of the following statements regarding chemical equilibrium is true?

Equilibrium is shown with a single arrow and/or an equal sign.

A system at equilibrium maintains the concentrations of all reactants/products over time.

A system at equilibrium stops.

Equilibrium is signified only with an equals sign.

Question 50

Which change in the nucleus of an atom is responsible for the emission of an electron?

neutron to proton

proton to neutron

proton to electron

electron to proton

Question 51

Which of the following is not true about beta emissions?

Difference of the atomic number by one between the old element and new element formed

Are written as 0-1e

Cannot penetrate concrete

Less penetrating than alpha emissions

Question 52

Which of the following represents positron emission?

3015P →   3014Si + ___

23892U  →  23490Th + ___

147N + 42He →   178O + ___

23490Th  →  23491Pa + ___