WorksheetsThermochemistry Review!
Total questions: 15
Worksheet time: 27mins
Name
Class
Date
1.
Chemical reactions that absorb energy are called
a)
endothermic
b)
fast
c)
slow
d)
exothermic
2.
A sample of iron receives 50.J of heat energy that raises the temperature of the iron 25.0°C. If iron has a specific heat of .10 J/g°C, what is the mass of the iron sample?
a)
25g
b)
30g
c)
20g
d)
50g
3.
If 238 J of heat is absorbed by a sample of metal with a mass of 40.7 g, and it raises the temperature from 20.0°C to 32.4°C, what is the specific heat capacity of the metal? (show your work)
a)
2.34 J/g°C
b)
0.472 J/g°C
c)
6.13 J/g°C
d)
0.163 J/g°C
4.
H2 + 2 C + N2 + 270.3 kJ --> 2 HCN
Is this reaction endothermic or exothermic?
Is this reaction endothermic or exothermic?
a)
Endothermic
b)
Exothermic
5.
What letter represents boiling?
a)
B
b)
C
c)
D
d)
E
6.
What letter represents a liquid being heated?
a)
A
b)
B
c)
C
d)
D
7.
How much energy does it take to freeze 39.2 g of liquid benzene (C6H6)? (ΔHfus = 9.08 kJ/mol, ΔHvap = 28.4 kJ/mol) (Show your work)
a)
4.940 kJ
b)
-4.940 kJ
c)
258 kJ
d)
-258 kJ
8.
Will H be positive or negative in this reaction?
a)
positive
b)
negative
9.
If ΔH is positive, heat would be shown on the _____ side of the thermochemical equation.
a)
Reactant
b)
Product
10.
Water exists as a _____________ at 700 mmHg and 50 °C.
a)
solid
b)
liquid
c)
gas
d)
supercritical fluid
11.
What change occurs from C to D?
a)
condensation
b)
vaporization
c)
melting
d)
sublimation
12.
What is the normal boiling point of this substance?
a)
150 °C
b)
100 °C
c)
-50 °C
d)
0 °C
13.
At 10 atm, dry ice is heated from -100 °C to 30 °C. What changes occur?
a)
freezing, then condensation
b)
melting only
c)
sublimation only
d)
melting, then boiling
14.
What phase change brings an increase in entropy?
a)
g->s
b)
l->s
c)
l->g
d)
g->l
15.
Which interval represents the heat of reaction for the reaction?
a)
A
b)
B
c)
D
d)
E
100 %
