Thermodynamics... in practice

Chemical energy is

• the energy stored within the structural units of chemical substances.

• the energy associated with the random motion of atoms and molecules

• energy available by virtue of an object's position

What is the main principle of the First Law of Thermodynamics?

• The energy in the universe is increasing

• The energy in the universe is decreasing

• The energy in the universe is constant

• The energy in the universe is determined by the amount of heat present

Which statement is correct about heat?

• Heat is a measure of the transfer of energy due to a temperature difference

• Heat transfer is always from hot to cold

• The heat gained by the surroundings equals the heat lost by the system

• All answers are correct

Which of the following processes always results in an increase in the energy of a system?

• The system loses heat and does work on the surroundings

• The system gains heat and does work on the surroundings

• The system loses heat and has work done on it by the surroundings

• The system gains heat and has work done on it by the surroundings

• None of these is always true

According to the Second Law of Thermodynamics, which of the following will never decrease in value for an isolated system?

• Temperature

• Volume

• Heat energy

• Entropy

What can be calculated using Hess's Law?

• The enthalpy change of a chemical reaction

• The energy used in a chemical reaction

• The entropy change of a chemical reaction

• All of these can be calculated using Hess's Law

The entropy of a gas increases with increasing temperature

• True

• False

Spontaneous processes always increase the entropy of the reacting system

• True

• False

Examine the reaction and estimate whether S is

positive, negative,or zero (no change):

2H2(g) + O2(g) -> 2H2O(g)

• Positive

• Negative

• Zero

Examine the reaction and estimate whether S is

positive, negative, or zero (no change):

Li+(aq) + Br-(aq) ->  LiBr(s)

• Positive

• Negative

• Zero