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Unit 3 Boss Battle

Total questions: 12

Worksheet time: 17mins

Name
Class
Date
1.
Some average bond enthalpies, in kJ/mol, are as follows:
H-H = 436
Cl-Cl = 242
H-Cl = 431
What is the enthalpy change for the decomposition of hydrogen chloride?
2 HCl --> H2 + Cl2
a)
-184 kJ
b)
+ 184 kJ
c)
- 247 kJ
d)
+ 247 kJ
2.

The enthalpy change for the reaction between hydrochloric acid and sodium hydroxide is −56 kJ/mol. Therefore ...

a)

the reaction is exothermic and the temperature rises

b)

the reaction is exothermic and the temperature falls

c)

the reaction is endothermic and the temperature rises

d)

the reaction is endothermic and the temperature falls

3.

What happens when chemical bonds are broken?

a)

Energy is released

b)

An explosion occurs

c)

An exothermic process take place

d)

An endothermic process take place

4.
What is meant by the Law of Conservation of Energy'?
a)
a) Energy lost can not be conserved
b)
b) Energy can neither be destroyed or created
c)
c) Temperature at start of reaction = Temperature at end of reaction
d)
d) Energy = Mass of products - Mass of Reactants
5.
Describe the energy change that takes place when bonds are made.
a)
a) Energy is given out
b)
b) Energy is taken in
c)
c) Energy is taken in and then given out
d)
d) Energy is given out and then taken in
6.
Describe the energy change that takes place when a chemical reaction occurs.
a)
a) Energy is given out
b)
b) Energy is taken in
c)
c) Energy is taken in and then given out
d)
d) Energy is given out and then taken in
7.
Which statement is true regarding endothermic reactions?
a)
a) Temperature change is positive and enthalpy change is positive
b)
b) Temperature change is positive and enthalpy change is negative
c)
c) Temperature change is negative and enthalpy change is positive
d)
d) Temperature change is negative and enthalpy change is negative
8.

Heat is measured in

a)

Joules

b)

grams

c)

°C

d)

J/g °C

9.

The specific heat of aluminum is 0.21 J/g°C. How much heat(Q) is released when a 10 g piece of aluminum foil is taken out of the oven and cools from 100° to 50°?

a)

-105 J

b)

10.5 J

c)

1.05 J

d)

105 J

10.

The specific heat(c) of copper is 0.39 J/g°C. What is the temperature change(∆T) when 100 Joules of heat(Q) is added to 20 grams?

a)

12.82 °C

b)

24.12°C

c)

351 °C

d)

780 °C

11.
The temperature of an unknown piece of metal with a mass of 30.00 g changes from 25.0 °C to 35.0 °C when the metal absorbs 350.0 J of energy. What is the specific heat of the metal?
a)
1.17 J/g°C
b)
-1.17 J/g°C
c)
0.857 J/g°C
d)
-0.857 J/g°C
12.

How much heat is needed to raise the temperature of 0.3g of copper from 25oC to 30oC. (Specific Heat of Copper= 0.38 J/g°C)

a)

0.57 J

b)

0.33 J

c)

2.3 J

d)

4.5 J