Name:_______________________________
Heat and Temperature
Video answers and explanations available at www.chemvideotutor.com/heat
1) Which transfer of energy occurs when ice cubes are placed in water that has a temperature of 45°C?
(1) Chemical energy is transferred from the ice to the water.
(2) Chemical energy is transferred from the water to the ice.
(3) Thermal energy is transferred from the ice to the water.
(4) Thermal energy is transferred from the water to the ice.
2) The average kinetic energy of water molecules is greatest in which of these samples?
(1) 10 g of water at 35°C (3) 100 g of water at 25°C
(2) 10 g of water at 55°C (4) 100 g of water at 45°C
3) What kelvin temperature is equivalent to –24°C?
4) What Celsius temperature is equal to 418 K?
5) Convert the melting point of iron metal to degrees Celsius.
Given the heating curve where substance X starts as a solid below its melting point and is heated uniformly:
6) Which line segments represent an increase in average kinetic
energy?
7) Which line segment represents an increase in potential energy and
no change in average kinetic energy?
8) What is happening to the average kinetic energy of the particles
during segment BC?
9) Describe, in terms of particle behavior or energy, what is
happening to substance X during line segment BC.
10) Identify the process that takes place during line segment DE of the heating curve.
11) How does this heating curve illustrate that the heat of vaporization is greater than the heat of fusion?
12) Using (•) to represent particles of substance X, draw at least five particles as they would appear in the substance at
point F.
Base your answers to questions 13 and 14 on the graph to the RIGHT,
which represents the cooling of a substance starting at a temperature
above its boiling point.
13) Which segment of the graph represents the gas phase, only?
14) What is the melting point of this substance?
Name:_______________________________
Heat and Temperature
Video answers and explanations available at www.chemvideotutor.com/heat
Base your answers to questions 15 through 17 on the information below.
A substance is a solid at 15°C. A student heated a sample of the solid substance and recorded the temperature at
one-minute intervals in the data table below.
15) On the grid to the LEFT, mark an appropriate scale on the axis
labeled “Temperature (°C).” An appropriate scale is one that allows a
trend to be seen. Then, plot the data from the data table. Circle and
connect the points.
16) Based on the data table, what is the melting point of this
substance?
17) The heat of fusion for this substance is 122 joules per gram. How
many joules of heat are needed to melt 7.50 grams of this substance
at its melting point? [Show ALL Work!]
18) How much heat energy must be absorbed to completely melt 35.0 grams of H2O(s) at 0°C? [Show ALL Work!]
The heat of vaporization of ethanol is 838 joules per gram. A sample of ethanol has a mass of 65.0 grams and is
boiling at 1.00 atmosphere.
19) Calculate the minimum amount of heat required to completely vaporize this sample of ethanol. Your response must
include both a correct numerical setup and the calculated result.
20) What is the total amount of heat energy, in joules, absorbed by 25.0 grams of water when the temperature of the water
increases from 24.0°C to 36.0°C? [Show ALL Work!]