Spring 2024
Lab 5 Assignment: Molar Volume of an Ideal Gas
Remember to report data and calculated results to the correct number of significant figures.
1. Write the balanced equation for the reaction between solid zinc and aqueous hydrochloric acid. Be sure
to include physical states.
2. Under what conditions of and did you measure volume? These are the temperature pressure
conditions that the molar volume value is valid. Record the (in °C) and (in initial temperature pressure
atm) to reference later. .Include units
T = 21.5ºC
P = 1.000atm
Determining the Experimental Average Molar Volume
In this part of the assignment you will calculate values for molar volume from experimental data
for each of your trials and then determine the average experimental molar volume.
3. Record and calculate the following for all three required trials.
Trial 1 Trial 2 Trial 3
a. Volume of 6.0 HCl used (mL)M 100mL 100mL 100mL
b
.
Moles of HCl reactant calculated using and Molarity Volume 0.060M 0.060M 0.060M
Show your work in this space (including result reported above) for Trial 1 only:
10ml HCl x 6M HCl = 0.010L HClx 6M HCl = 0.060M HCl
c. Mass of zinc used (g) [Report all three sig figs] 0.100g 0.015g 0.200g
d
.
Molar mass of zinc (g/mol) [General Rule: Use at least 4
significant figures from periodic table]
65.39 g/mol 65.39 g/mol 65.39
g/mol
e. Moles of zinc reactant calculated using the molar mass 0.00153 mol 0.00229mol 0.00306
mol
Show your work in this space (including result reported above) for Trial 1 only:
0.100g Zn x (1Mole zn/65.39g Zn) = 0.00153mol Zn
f. Identity of Limiting Reactant zinc zinc zinc
g
.
Volume of gas produced, measured at initial room
temperature (mL)
36.81mL 55.23mL 73.62mL
hMoles of H gas produced
2 using stoichiometry from limiting 0.00153 0.00229 0.00306
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Name: Date: 04/11/2024WilnerMaurice
. Zn(s) + 2 HCl(aq) = ZnCl2(aq) + H2(g)
Trial 1 Trial 2 Trial 3
.
reactant (mol) mol mol mol
Show your work in this space (including result reported above) for Trial 1 only:
Since zinc is limiting, the number of moles of hydrogen gas produced
equals the moles of zinc = 0.00153mol
4. Calculate from your data above by dividing the volume of an experimental value for molar volume
gas produced by the moles of gas produced:
Molar volume = (volume of gas)/(moles of gas) = V/n
Trial 1 Trial 2 Trial 3
Calculated Molar Volume of the hydrogen gas at room
temperature (Volume/moles), expressed in units of L/mol,
calculated from your experimental data. [Report with 4 significant
figures (one extra)]
24.07L/mol 24.08L/mol 24.07L/mol
Show your work in this space (including result reported above) for Trial 1 only:
36.81ml(1L/1000mL) = 0.03681L = V
n = 0.100g Zn(1M Zn/65.39g Zn) = 0.001529mol Zn
V/n = 0.03681L/0.001529mol = 24.0701 L/mol = 24.07L/mol
5. at 21.5 °CCalculate the experimental molar volume average from Trials 1, 2 and 3 with units of
L/mol. This is your . [Report with 3 significant figures]experimental value
Show calculation with answer that includes and correct units significant figures:
(24.0701+24.0766+24.0701)/3 =24.0723=24.1
Answer:
24.1L/mol
6. Compare the experimental molar volumes obtained in all three trials. Do you expect the molar volume
values to be similar? Explain your reasoning. Yes because zinc was the limiting reactant and with
stoichiometry we know Zn and H are in a 1 to 1 ratio
2
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Determining the Theoretical Molar Volume
In this part of the assignment you will be using the ideal gas law equation:
PV=nRT where R = 0.08206 L·atm/(K·mol)
7. Calculate the of an ideal gas under the same conditions of theoretical value of the molar volume
temperature and pressure used in your experiment (refer to Question 2). To solve for molar volume,
rearrange the ideal gas law equation so you are with an answer with l. solving for V/n units of L/mo
Show calculation with answer that includes and correct units significant figures:
Pv=nRT -> V/n = RT/P
[0.08206 (L x Atm/mol x K) x 295.65K]/1.000atm = 24.261L/mol = 24.26L/mol
Answer:
24.26L/mol
8. Compare the value for the molar volume at 21.5 °C (from Question 5) with the average experimental
theoretical “ideal” value at the same temperature (from Question 7).
a. Experimental Average Molar Volume from Trials 1, 2 and 3 (L/mol).
This is your . [Report with 3 significant figures]experimental value
24.1L/mol
b. Ideal Molar volume from #7 (L/mol). This is your theoretical value.24.26L/mol
c. Explain any differences between these two values for molar volume. If there is no difference,
explain why you should expect a difference.
The differences are because we never have a perfect experiment. All tools that we used to measure
like beakers and flasks shall always have a percent error based on rounding and what we perceive to
be the correct value.
9. Use your from the first row in the above table to predict the volume experimental molar volume value
of 3.31 mol of hydrogen gas under the same conditions of temperature and pressure as your experiment.
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Show calculation with answer that includes and correct units significant figures:
V=RTn/P = [0.08206 (L x Atm/mol x K) x 295.65K x 3.31M H ]/1.000atm = 80.304L =80.3L H
2 2
