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An Introduction to Thermochemistry

Total questions: 20

Worksheet time: 46mins

Name
Class
Date
1.

The minimum energy particles must have to react is the

a)

acting energy

b)

active energy

c)

activation energy

2.

Which letter shows the activation energy

a)

A

b)

B

c)

C

3.

Is this showing an endothermic or an exothermic reaction?

a)

Endothermic

b)

Exothermic

4.

Which letter shows the heat change?

a)

A

b)

B

c)

C

d)

D

e)

E

5.

Which letter represents the reactants?

a)

A

b)

B

c)

C

d)

D

e)

E

6.

Which letter represents the products?

a)

A

b)

B

c)

C

d)

D

e)

E

7.

Which letter represents the transition state?

a)

A

b)

B

c)

C

d)

D

e)

E

8.
During an endothermic reaction in a beaker if we are part of the surroundings and touched the beaker, it would feel _______. 
a)
Warm
b)
Cold
9.
Define 'Enthalpy'
a)
a) Energy stored in the movement of molecules in a substance
b)
b) The opposite of temperature
c)
c) The temperature of a molecule
d)
d) Energy stored in the chemical bonds in a substance
10.

What is the Heat of Reaction ΔH\Delta H  for this reaction?

a)

-200 KJ

b)

200 KJ

c)

400 KJ

d)

-300 KJ

11.

When heat flows from system to the surroundings that is an example of an ________________ process.

a)

exothermic

b)

endothermic

12.

The potential energy diagram of a reaction is shown. Which statement below is correct relating to this reaction?

a)

#1 represents the enthalpy change for this exothermic reaction.

b)

#2 represents the enthalpy change for this endothermic reaction.

c)

#3 represents the enthalpy change for this endothermic reaction.

d)

#4 represents the enthalpy change for this exothermic reaction.

13.
Is the combustion of gasoline endothermic or exothermic?
a)
Endothermic
b)
Exothermic
14.
Refer the the following question:
2N2 + 3H2 --> 2NH3 + 46 kJ
How much energy would be produced if only 1 mol of nitrogen was reacted?
a)
92 kJ
b)
0.143 kJ
c)
23 kJ
d)
15 kJ
15.
How much energy must be used to produce 4.75 mol of gaseous water?
H2O (l) +  44.0 kJ --> H2O (g)
a)
207 kJ
b)
9.36 kJ
c)
206.8 kJ
d)
9.362 kJ
16.
4 PCl5 + 3438 kJ --> P4 + 10 Cl2
How much energy is required to produce each mole of chlorine?
a)
687.6 kJ
b)
859.5 kJ
c)
343.8 kJ
d)
245.8 kJ
17.
H2 + Cl2 --> 2 HCl + 1845 kJ
Is this reaction endothermic or exothermic?
a)
Endothermic 
b)
Exothermic
18.
H2 + 2 C + N+ 270.3 kJ --> 2 HCN
Is this reaction endothermic or exothermic?
a)
Endothermic 
b)
Exothermic
19.

How many moles of P4 must be reacted to produce 5905 kJ of energy? P4 + 6Cl2 --> 4PCl3 + 2439 kJ

a)

2

b)

1

c)

4

d)

8

20.

Refer the the following question: 2N2 + 3H2 --> 2NH3 + 46 kJ How much energy would be produced if 6 mol of hydrogen gas was reacted?

a)
92 kJ
b)
0.143 kJ
c)
23 kJ
d)
15 kJ