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28 questions
an element
a compound
a homogeneous mixture
a heterogeneous mixture
Which particle diagram represents a sample of matter that CANNOT be broken down by chemical change?
Object A at 40^{o}C and object B at 80^{o}C are placed in contact with each other. Which statement describes the heat flow between the objects?
Heat flows from object A to object B.
Heat flows from object B to object A.
Heat flows in both directions between the objects.
No heat flow occurs between the objects.
What occurs when a 35-gram aluminum cube at 100^{o}C is placed in 90. grams of water at 25^{o}C in an insulated cup?
Heat is transferred from the aluminum to the water, and the temperature of the water decreases.
Heat is transferred from the aluminum to the water, and the temperature of the water increases.
Heat is transferred from the water to the aluminum, and the temperature of the water decreases.
Heat is transferred from the water to the aluminum, and the temperature of the water increases.
What is the total amount of heat required to vaporize 1.00 gram of H_{2}O(l) at 100^{o}C and 1 atmosphere?
4.18 J
334 J
373 J
2260 J
Which process is exothermic?
boiling of water
melting of copper
condensation of ethanol vapor
sublimation of iodine
The graph represents the relationship between temperature and time as heat is added to a sample of H_{2}O. Which statement correctly describes the energy of the particles of the sample during interval BC?
Potential energy decreases and average kinetic energy increases.
Potential energy increases and average kinetic energy increases.
Potential energy increases and average kinetic energy remains the same.
Potential energy decreases and average kinetic energy remains the same.
The graph represents the uniform heating of a substance, starting below its melting point, when the substance is solid. Which line segments represent an increase in average kinetic energy?
AB and BC
AB and CD
BC and DE
DE and EF
The graph shows the heating curve of 1.0 gram of a solid as it is heated at a constant rate, starting at a temperature below its melting point. Based on this graph, what is the heat of vaporization?
200 calories, as measured along line BC
250 calories, as measured along line BC
400 calories, as measured along line DE
800 calories, as measured along line DE
A student obtained the data in the table while cooling a substance. The substance was originally in the liquid phase at a temperature below its boiling point. What is the freezing point of the substance?
70^{o}C
59^{o}C
53^{o}C
48^{o}C
The graph was constructed by a student to show the relationship between temperature and time as heat was uniformly added to a solid below its melting point. What is the total length of time that the solid phase existed with the liquid phase?
6 min
10 min
8 min
4 min
A 36-gram sample of water has an initial temperature of 22^{o}C. After the sample absorbs 1200 joules of heat energy, the final temperature of the sample is
8.0^{o}C
14^{o}C
30.^{o}C
55^{o}C
The temperature of a sample of water changes from 10.^{o}C to 20.^{o}C when the water absorbs 420 Joules of heat. What is the mass of the sample?
1.0 g
10 g
100 g
1000 g
An 80.0-gram sample of water at 10.0^{o}C absorbs 1680 Joules of heat energy. What is the final temperature of the water?
50.0^{o}C
15.0^{o}C
5.00^{o}C
4.00^{o}C
How many Joules of heat energy are released when 50. grams of water are cooled from 70.^{o}C to 60.^{o}C?
42 J
210 J
2100 J
4200 J
What is the total number of kiloJoules of heat energy absorbed when the temperature of 200 grams of water is raised from 10^{o}C to 40^{o}C?
0.126 kJ
0.840 kJ
25.2 kJ
33.6 kJ
What is the minimum amount of heat required to completely melt 20.0 grams of ice at its melting point?
20.0 J
83.6 J
6,680 J
45,200 J
At which Celsius temperature does lead change from a solid to a liquid? (Hint: Use reference tables S and T.)
874^{o}C
601^{o}C
328^{o}C
0^{o}C
How much energy is required to vaporize 10.00 grams of water at its boiling point?
2.26 kJ
3.34 kJ
4.2 kJ
22.6 kJ
Which phase change at STP represents sublimation?
CO_{2}(s) → CO_{2}(g)
H_{2}O(s) → H_{2}O(l)
CO_{2}(l) → CO_{2}(g)
H_{2}O(l) → H_{2}O(s)
The diagram represents a portion of a thermometer that is measuring the temperature of a solution. According to the thermometer, the temperature of the solution is
13.50^{o}C
13.5^{o}C
16.50^{o}C
16.5^{o}C
A sample of an element has a mass of 34.261 grams and a volume of 3.8 cubic centimeters. To which number of significant figures should the calculated density of the sample be expressed?
5
2
3
4
A student determined the heat of fusion of water to be 88 calories per gram. If the accepted value is 80. calories per gram, what is the student's percent error?
8.0%
10.%
11%
90.%
At a pressure of 101.3 kilopascals and a temperature of 373 K, heat is removed from a sample of water vapor, causing the sample to change from the gaseous phase to the liquid phase. This phase change is represented by the equation below:
H_{2}O(g) → H_{2}O(l) + heat
Determine the total amount of heat released by 5.00 grams of water vapor during this phase change.
A 100.0-gram sample of NaCl(s) has an initial temperature of 0^{o}C. A chemist measures the temperature of the sample as it is heated. Heat is not added at a constant rate. The heating curve for the sample is shown in the graph.
Identify one line segment on the curve where the average kinetic energy of the particles of the NaCl sample is changing.
A 5.00-gram sample of liquid ammonia is originally at 210. K. The diagram of the partial heating curve represents the vaporization of the sample of ammonia at standard pressure due to the addition of heat. The heat is not added at a constant rate.
Some physical constants for ammonia are shown in the data table.
Determine the total amount of heat required to vaporize this 5.00-gram sample of ammonia at its boiling point.
A 5.00-gram sample of liquid ammonia is originally at 210. K. The diagram of the partial heating curve represents the vaporization of the sample of ammonia at standard pressure due to the addition of heat. The heat is not added at a constant rate.
Some physical constants for ammonia are shown in the data table.
Describe what is happening to the potential energy and the average kinetic energy of the molecules in the ammonia sample during time interval BC.
A 5.00-gram sample of liquid ammonia is originally at 210. K. The diagram of the partial heating curve represents the vaporization of the sample of ammonia at standard pressure due to the addition of heat. The heat is not added at a constant rate.
Some physical constants for ammonia are shown in the data table.
Calculate the total heat absorbed by the 5.00-gram sample of ammonia during time interval AB.
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