Question #1: Two substances have different Change H fusion values. If given the same number of moles of each substance, and assuming the same amount of heat is applied to both substances, the substances with the lower change H fusion value will convert from a solid to a liquid more quickly. True or False
Question #2: When a change G =0, which of the following is not true?
a) the reaction can spontaneously proceed in the forward direction
b) the reaction can spontaneously proceed from the products to the reactants
c) the reaction requires no heat to proceed
d) Neither the forward or reverse reaction is favored
Question #3: Which of the following will not favor a spontaneous change?
1) + Change S
2) – Change S
3) + Change H
4) – Change H
a) II only
b) II and III
c) III only
d) I and II
Question #4 : What amount of heat is exchanged when 106.2 grams of substance Y goes from a liquid at 35 degrees Celsius to a solid at the same temperature? Melting point of substance Y=35 degrees C ; Change H vaporization=3.67J/mol; Change H fusion = 3.30 J/mol. MW substance y=28.22g/mol.
a) -12.4 J
b) -3.51 x 10 ^2J
C) 1.24 x 10 ^1J
d) 351 J
Question #5 The enthalpy change for the reaction, 2CO (g) + 02(g) —> 2CO2 (g), can be calculated from Change Hf values for each reactant and product. Which substance or substances in this equation have a change Hf value equal to 0.0 kj?
a) O2 (g)
c) 02(g) and CO(g)
d) CO2 (g)
Question #6: Which of the following statements concerning the reaction shown below are true? P4(s) + 302(g)—->P406(s). Change H =1640kj
1) heat is absorbed
2) heat is released
3) rx is exothermic
4) rx is endothermic
5) products have higher enthalpy content than reactants
6) reactants have higher enthalpy content than products
a) I, III,V
b) II,III, V
c) II, III, VI
d) I, III
Question #7: A substance of unknown mass absorbs 1932 joules of energy, going from 26-42 degrees Celsius. If the specific heat of the substance is 4.29J/g.C, how much of the substance is present?
1) 2.8 g