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WorksheetsPT 1 - Basic Concepts in Thermochemistry
Total questions: 20
Worksheet time: 5hrs 36mins
Which of the following statements is FALSE?
The energy of the universe is constant.
Work is negative (-) if the system is the one doing the work.
Internal energy can be determined through determining the heat and work of the system.
The melting of ice when placed in someone's hand is considered endothermic if the system being studied is the hand itself.
The energy gained by the surroundings must be equal to the energy lost by the system.
Objects can possess energy as:
A. Endothermic Energy
B. Potential Energy
C. Kinetic Energy
A only
B only
C only
A and C
B and C
Calculate the ΔE for a system undergoing an endothermic system in which 15.6 kJ of heat flows and where 1.4 kJ of work is done on the system.
-17 kJ
+17 kJ
-14.2 kJ
+14.2 kJ
The answer cannot be determined
The internal energy of a system is ALWAYS increased by _________.
Adding heat to the system
Having the system do work on the surroundings
Withdrawing heat from the system
Adding heat to the system and having the system do work on the surroundings
A volume decompression
Which of the following is an endothermic process?
Ice melting
Water freezing
Boiling soup
Hydrochloric acid and barium hydroxide are mixed at 25°C : the temperature increases
Melting of ice and boiling soup
When a system _________, ΔE is ALWAYS negative.
Absorbs heat and does work
Gives off heat and does work
Absorbs heat and has work done on it
Gives off heat and has work done on it
None of the above is ALWAYS negative
Which of the following is an exothermic process?
Ice melting
Water evaporating
Boiling soup
Condensation of water vapor
Ammonium thiocyanate and barium hydroxide are mixed at 25°C : the temperature drops
Which of the following is a statement of the first law of thermodynamics?
Ek=2 1mv2
A negative ΔH corresponds to an exothermic process
ΔE=Efinal−Einitial
Energy lost by the system must be gained by the surroundings
1 cal = 4.184 J (exactly)
The internal energy can be increased by ________.
A. Transferring heat from the surroundings to the system
B. Transferring heat from the system to the surroundings
C. Doing work on the system
A only
B only
C only
A and C
B and C
The ΔE of a system that releases 12.4 J of heat and does 4.2 J of work on the surroundings is ________ J.
16.6
12.4
4.2
-16.6
-8.2
The ΔE of a system that absorbs 12.4 J of heat and does 4.2 J of work on the surroundings is _________ J.
16.6
12.4
4.2
-16.6
8.2
A 100-watt electric incandescent light bulb consumes ____ J of energy in 24 hours. Note that 1 Watt (W) = 1 J/sec.
2.40 ×103
8.64×103
4.17
2.10 ×103
8.64×106
Convert 427.34 kWh to kilojoules (kJ).
15 384
1.54 ×109
1 538 424
1.187
842.42
The change in the internal energy of a system that absorbs 2500 J of heat and that does 7655 J of work on the surroundings is ________ J.
10 155
5 155
-5 155
-10 155
1.91×107
The energy required to turn on two incandescent bulbs is 538 kWh. Convert this value in kilocalories (kcal).
462 906
62 528
810 357
15 062
26 162
Calculate the work done (kJ) during a reaction in which the internal volume expands from 19 L to 48 L against an outside pressure of 253.13 kPa.
-7.3 kJ
17 kJ
7.3 kJ
-17 kJ
0 kJ
When work is done on the system, it will be a _____ value.
positive
negative
very large
very small
There is not enough information to determine the correct answer
This is the energy used to move an object against a force.
(a)
A _____ ΔH corresponds to an ______ process.
negative, endothermic
negative, exothermic
positive, exothermic
zero, exothermic
zero, endothermic
The value of ΔE for a system that performs 19 kJ of work on its surroundings and loses 9 kJ of heat is ____ kJ.
-28
28
171
10
-10
