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WorksheetsUnit 5B Chemical thermochemistry review
Total questions: 45
Worksheet time: 1hrs 29mins
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.
As someone is running on the track they begin to perspire. If the runner is our system, are they endothermic or exothermic?
a)
Endothermic process
b)
Exothermic process
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?
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)
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
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?
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?
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?
Is this reaction endothermic or exothermic?
a)
Endothermic
b)
Exothermic
14.
If the enthalpy ter (ΔH) is negative the reaction is ____.
a)
Endothermic
b)
Exothermic
c)
Neutral
15.
H2 + ½ O2 --> H2O + 285kJ is an example of a(n)
a)
Electrical equation
b)
Heat equation
c)
Thermochemical equation
16.
If ΔH is positive, heat would be shown on the _____ side of the thermochemical equation.
a)
Reactant
b)
Product
17.
Energy transfered between samples of matter because of a difference in their temperature.
a)
Temperature
b)
Enthalpy
c)
Entropy
d)
Heat
18.
How much heat does an aluminum block absorb if 10.00 grams ae heated from 25.0oC to 50.0oC? the specific heat of aluminum is .900J/goC
a)
450
b)
-450
c)
225
d)
-225
19.
C+ O2 --> CO2 + 60kJ, what is the value for ΔH for the reaction?
a)
+60
b)
-60
c)
there is no way to know
20.
The diagram represents which type of reaction
a)
endothermic
b)
exothermic
21.
When you dropped a hot metal sample into room temperature water in the lab what happened?
a)
the heat from the metal traveled into the water
b)
the cool from the water traveled into the hot metal
c)
both of the other answers are correct
22.
What kind of graph is this?
a)
endothermic
b)
exothermic
23.
Which of the letters (A-D) represents activation energy?
a)
A
b)
B
c)
C
d)
D
24.
Which of the letters (A-D) represents the potential energy of the reactants?
a)
A
b)
B
c)
C
d)
D
25.
Which of the letters (A-D) represents the potential energy of the products?
a)
A
b)
B
c)
C
d)
D
26.
What kind of reaction has a positive heat of reaction (ΔHr)?
a)
endothermic
b)
exothermic
27.
Compared to the potential energy of the products, the potential energy of the reactants above is?
a)
greater than
b)
less than
c)
the same
d)
impossible to determine
28.
What kind of reaction has a negative heat of reaction (ΔHr)?
a)
endothermic
b)
exothermic
29.
What kind of reaction is this?
a)
endothermic
b)
exothermic
30.
A process that absorbs heat is a(n) _______________ reaction?
a)
polythermic
b)
ergothermic
c)
exothermic
d)
endothermic
31.
Consider the reaction: 2 H2O + energy --> 2H2 + O2
a)
exothermic, releasing energy
b)
exothermic, absorbing energy
c)
endothermic, absorbing energy
d)
endothermic, releasing energy
32.
The minimum amount of energy needed to start a reaction is called the?
a)
surface energy
b)
activation energy
c)
concentration
d)
catalyst
33.
What is the highest point in PE?
a)
activated complex
b)
activation energy
34.
Thermal energy ALWAYS moves from _____ to _____.
a)
solid to liquid
b)
ice to water
c)
hot to cold
d)
solid to gas
35.
LT3: If two objects have different temperatures, heat will flow from the warmer object to the cooler one UNTIL ____________
a)
one reaches a temperature of zero
b)
they both have an equal temperature
c)
one runs out of energy
36.
If the specific heat of water is 4.18 J/g∙°C, how much heat is required to increase the temperature of 1.2 kg of water from 23 °C to 39 °C?
a)
-80,256 J
b)
80.256 J
c)
80,256 J
d)
-80.256 J
37.
What does "q" mean?
a)
A change in health
b)
A change in heat
c)
A change in height
d)
A change in temperature
38.
What does "ΔT" mean?
a)
A change in health
b)
A change in heat
c)
A change in height
d)
A change in temperature
39.
What information does the specific heat capacity of water tell us?
a)
How much energy was released in the combustion of our food item
b)
The amount of energy to raise the temperature of 1 gram of water 1 Celsius degree
c)
The amount of energy in our water when we started the calorimetry lab
d)
It is just a constant to help us cancel units
40.
What is the formula to calculate heat energy required to raise the temperature of any substance?
a)
Q=mc∆t
b)
Q=mc
c)
Q= ½mv
d)
m=QC
41.
The symbol for specific heat is .......
a)
c
b)
Q
c)
m
d)
t
42.
If two objects have different temperatures, heat will flow from the warmer object to the cooler one UNTIL ____________
a)
one reaches a temperature of zero
b)
they both have an equal temperature
c)
one runs out of energy
43.
Calorimetry Question:
A piece of metal with a mass of 32.8 g is heated to 100.5°C and dropped into 138.2 g of water at 20.0°C. The final temperature of the system is 30.2°C. What is the specific heat capacity of the metal? (show your work)
A piece of metal with a mass of 32.8 g is heated to 100.5°C and dropped into 138.2 g of water at 20.0°C. The final temperature of the system is 30.2°C. What is the specific heat capacity of the metal? (show your work)
a)
2.56 J/g°C
b)
0.391 J/g°C
c)
5.29 J/g°C
d)
3.50 J/g°C
44.
What does "ΔH" mean?
a)
A change in health
b)
A change in heat
c)
A change in height
d)
A change in temperature
45.
What is a tool that measures the heat of chemical reactions?
a)
calorimeter
b)
calorie
c)
Styrofoam™ cup
d)
none of these
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