Chemistry
Section
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Name:
CH 12-13 STUDY GUIDE
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Date:
Short Answer.
1. A rigid cylinder with a movable piston contains a 2.0-liter sample of neon gas at STP.
What is the volume of this sample when its temperature is increased to 30.°C while its
pressure is decreased to 90. kilopascals? Your answer must include both a correct
numerical setup and the calculated result.
V1 = 2.0 L
V2 = ?
T1 = 273 K
T2 = 303 K
P1 = 101.3 kPa
P2 = 90. kPa
V . . .
2.5L
2.5 L
Base your answers to questions 2 through 4 on the information below.
A 100.0-gram sample of NaCl(s) has an initial temperature of 0°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 below.
2. Determine the temperature range over which the entire NaCl sample is a liquid.
801°C to 1465°C or CD
3. Identify one line segment on the curve where the average kinetic energy of the particles of
the NaCl sample is changing.
AB or CD
4. Identify one line segment on the curve where the NaCl sample is in a single phase and
capable of conducting electricity.
CD
Created on 18 March 2014
Base your answers to questions 5 and 6 on the information below.
A student performed an experiment to determine the total amount of energy stored in a
peanut. The accepted value for the energy content of a peanut is 30.2 kilojoules per gram.
The student measured 100.0 grams of water into a metal can and placed the can on a ring
stand, as shown in the diagram below. The peanut was attached to a wire suspended under the
can. The initial temperature of the water was recorded as 22.0°C. The peanut was ignited and
allowed to burn. When the peanut finished burning, the final water temperature was recorded as
57.0°C. The student’s experimental value for the energy content of this peanut was
25.9 kilojoules per gram.
5. Calculate the total amount of heat absorbed by the water. Your answer must include both a
correct numerical setup and the calculated result.
q
mC∆T
100.0g
4.18Jg – K – 35.0K
= 14 630 J
6. Determine the student’s percent error for the energy content of this peanut.
%
experimental accepted
accepted
= –14.2 %
100%
25.9kJg –
30.2kJg – 30.2kJg –
100%
Base your answers to questions 7 through 9 on the information below.
A 150.-gram liquid sample of stearic acid, C17H35COOH, is cooled at a constant rate. The
temperature of the sample is recorded at 2-minute intervals in the data table below.
7. Identify the physical change occurring during the time interval 4 minutes to 10. minutes.
The sample is freezing
8. On the grid below:


Mark an appropriate scale on the axis labeled “Temperature (°C).”
Plot the data from the data table. Circle and connect the points.
9. Determine the gram-formula mass of stearic acid.
C: 17 ( 12.011 )
H: 36 ( 1.00794 )
O: 2 ( 15.9994 )
272.47 g mole–1