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Thermochemistry Matriculation Intro

Total questions: 20

Worksheet time: 58mins

Name
Class
Date
1.
In an exothermic process the surrounding looses heat. 
a)
True
b)
False
2.
In an endothermic reaction the system is releasing energy.
a)
True
b)
False
3.
Is the combustion of gasoline endothermic or exothermic?
a)
Endothermic
b)
Exothermic
4.
A reaction is performed in a beaker with a temperature probe recording the temperature changes of the reaction.  If the temperature began at 15.0 degrees Celsius and ended at 27.5 degrees Celsius.  If the reaction is our system, is the system endothermic or exothermic?
a)
Exothermic
b)
Endothermic
5.
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
6.
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
7.
What mass of P4 must be reacted to produce 5905 kJ of energy?
P4 + 6Cl2 --> 4PCl3 + 2439 kJ
a)
25.43 g
b)
563.0 g
c)
2.421 g
d)
300.0 g
8.
Do reactants in an endothermic reaction have a higher or lower energy than the products? 
a)
Higher
b)
Lower
9.
Do the reactants in an exothermic reaction have a higher or lower energy than the products?
a)
Higher
b)
Lower
10.
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
11.

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

c)

Bubbly

d)

Damp

12.
H2 + Cl2 --> 2 HCl + 1845 kJ
Is this reaction endothermic or exothermic?
a)
Endothermic 
b)
Exothermic
13.
H2 + 2 C + N2 + 270.3 kJ --> 2 HCN
Is this reaction endothermic or exothermic?
a)
Endothermic 
b)
Exothermic
14.

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.

15.

The diagram represents two solids and the temperature of each. What occurs when the two solids are placed in contact with each other?

a)

Heat energy flows from solid A to solid B. Solid A decreases in temperature

b)

Heat energy flows from solid A to solid B. Solid A increases in temperature

c)

Heat energy flows from solid B to solid A. Solid B decreases in temperature.

d)

Heat energy flows from solid B to solid A. Solid B increases in temperature.

16.
Heat flows from _______ to ______ objects
a)
cooler to warmer
b)
warmer to warmer
c)
warmer to cooler
d)
cooler to cooler
17.
Heat is measured in 
a)
joules
b)
grams
c)
degrees celcius
18.
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
19.
A chemical reaction that absorbs heat from the surroundings is said to be __________ and has a __________ ΔH at constant pressure.
a)
endothermic; positive
b)
endothermic; negative
c)
exothermic; negative
d)
exothermic; positive
20.

Choose a substance with enthalpy of formation not equal to zero

a)

Iodine (solid)

b)

Sodium (solid)

c)

Bromine (liquid)

d)

Carbon dioxide (gas)