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Lab: Molar Volume of Hydrogen Gas

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Part 1
The following are the givens from the experiment:
Initial Experiment with 10mL- 6 M HCl and 0.25g Zinc
Initial Teperature = 21.5C
Initial Pressure = 1.00atm
After adding 0.25g Zinc - The solution reacted
Pressue = 1.69atm
Temperature = 27.3C
Volume in Syrenge = 92.2mL
Volume in Flask = 9.9mL

Part 2
Repeated Experiment with 10mL- 6 M HCl and 0.5g of Zinc
Initial Temperature = 21.5C
Initial Pressure = 1.00atm
After adding 0.5g Zinc -The solution reacted
Pressure = 2.41atm
Temperature =33.4C
Volume in Syrenge = 184.5mL
Volume in Flask = 9.8mL

The following answers are what I have so far: Need to know if A,B,C,D,E, & F are correct for 1 & 2 if not please correct.

1. Record and calculate the following for the first half of the experiment:
a. Mass of zinc used (g) = 0.25g
b. Volume of 6M HCl used (mL) = 10mL
c. Molecular weight of zinc (g/mol) = 65.409 g/mol
d. Moles of zinc reacted = 0.25 g / 65.41 g/mol= 0.00382 moles
e. Moles of hydrogen produced = 0.00382 moles
f. Molar volume of the ideal hydrogen gas at room temperature (Volume/moles), expressed as L/mol at X degrees C and a pressure of 1 atmosphere = 22.4 L/mole * 0.00382 moles = 0.0856 L or 85.6mL

2. For the second part of the experiment, everything was the same except that twice as much Zn was used. Record and calculate the following for this second reaction:
a. Mass of zinc used (g) = 0.50
b. Volume of 6M HCl used (mL) = 10mL
c. Molecular weight of zinc (g/mol) = 65.409 g/mol
d. Moles of zinc reacted = 0.50 g / 65.41 g/mol=0.00764
e. Moles of hydrogen produced = 0.00764 moles
f. Molar volume of the ideal hydrogen gas at room temperature (Volume/moles), expressed as L/mol at X degrees C and a pressure of 1 atmosphere = 22.4 L/mole * 0.00764 moles = 0.1711 L

Also need the following answered from the above information: Numbers 3, 4, & 5

3. Compare the molar volumes obtained in the two parts of the experiment. What difference did using twice the amount of Zn in the second part?

4. Which is the limiting reactant - zinc or HCl? I think HCl

5. Compare the experimental value for the molar volume at 21C with the value listed in the Background section of the lab manual. Calculate the experimental error according to: % error = | experimental molar volume - listed molar volume | / (listed molar volume) * 100%

Background

Robert Boyle found that, under isothermal conditions (constant temperature), the pressure of a gas is inversely proportional to its volume. This also means that the product of the pressure and volume is a constant. The equations that describe this relationship are
P × V = constant
and
P1 × V1 = P2 × V2
Jacques Charles found that the volume of a gas under isobaric conditions (constant pressure) is directly proportional to its temperature. As the temperature increases so does the volume that the gas occupies. The equations that describe this relationship are:
V ÷ T= constant
and
V1 ÷ T1 = V2 ÷ T2
It is possible to combine Boyle's law and Charles' law:
P1 × V1 ÷ T1 = P2 × V2 ÷ T2
The Ideal Gas Law includes the dependence of the volume on the number of gas moles, and an experimentally determined proportionality constant, called the Universal Gas Constant, which is designated by R.
The mathematical formulation of the law is written as follows:
(P × V) ÷ (n × T) = R
or in the more familiar form:
P × V = n × R × T
The value for the Universal Gas Constant, R, is 8.314472 J/mol*K (Joules per mole per degree Kelvin).
One important result of the Ideal Gas Law is that under conditions of constant pressure and temperature, one mole of any gas will always occupy the same volume.
The volume that one mole of an ideal gas occupies when held at a specific temperature and pressure is referred to as a "molar volume". For example, at one atmosphere, the molar volume of any ideal gas is 22.414 L/mol at 0 °C and 24.137 L/mol at 21°C. Most gases follow the Ideal Gas Law closely at atmospheric pressure and room temperature.
In this experiment you will determine the molar volume of hydrogen gas and compare it with the value predicted by the Ideal Gas Law. Hydrogen gas is produced in the following reaction between zinc and hydrochloric acid:
Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)
One can calculate the molar volume of the gas at room temperature and pressure according to the equation:
Molar volume (L/mol) = (measured volume) ÷ (number of moles)
To complete this lab you will need to:
Calculate the number of moles of H2 produced. (Hint: For every mole of zinc used in the reaction, one mole of H2 is produced.)
Measure the volume of H2 gas produced.

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Solution Preview

Part 1
The following are the givens from the experiment:
Initial Experiment with 10mL- 6 M HCl and 0.25g Zinc
Initial Teperature = 21.5C
Initial Pressure = 1.00atm
After adding 0.25g Zinc - The solution reacted
Pressure = 1.69atm
Temperature = 27.3C
Volume in Syrenge = 92.2mL
Volume in Flask = 9.9mL

Part 2
Repeated Experiment with 10mL- 6 M HCl and 0.5g of Zinc
Initial Temperature = 21.5C
Initial Pressure = 1.00atm
After adding 0.5g Zinc -The solution reacted
Pressure = 2.41atm
Temperature =33.4C
Volume in Syrenge = 184.5mL
Volume in Flask = 9.8mL

The following answers are what I have so far: Need to know if A,B,C,D,E, & F are correct for 1 & 2 if not please correct.

1. Record and calculate the following for the first half of the experiment:
a. Mass of zinc used (g) = 0.25g
b. Volume of 6M HCl used (mL) = 10mL
c. Molecular weight of zinc (g/mol) = 65.409 g/mol
d. Moles of zinc reacted = 0.25 g / 65.41 g/mol= 0.00382 moles
e. Moles of hydrogen produced = 0.00382 moles
f. Molar volume of the ideal hydrogen gas at room temperature (Volume/moles), expressed as L/mol at X degrees C and a pressure of 1 atmosphere = 22.4 L/mole * ...

Solution Summary

This solution offers detailed step-wise calculations to a chemistry lab related to molar volume of hydrogen.

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See Also This Related BrainMass Solution

Hydrogen from Zinc and Hydrochloric Acid Experiment ( H2 from Zn and HCl Experiment )

This is the background

Robert Boyle found that, under isothermal conditions (constant temperature), the pressure of a gas is inversely proportional to its volume.

This also means that the product of the pressure and volume is a constant. The equations that describe this relationship are:

P*V= constant
and

P1V1 = P2V2

Jacques Charles found that the volume of a gas under isobaric conditions (constant pressure) is directly proportional to its temperature. As the temperature increases so does the volume that the gas occupies.

The equations that describe this relationship are:

V/T= constant

and

V1/T1 = V2/T2

It is possible to combine Boyle's law and Charles' law into a combined gas law:

P1*V1/T1 = P2*V2/T2

The Ideal Gas Law includes the dependence of the volume on the number of gas moles, and an experimentally determined Universal Gas Constant, R.

This law is written as follows:

(P*V) / (n*T) = R (the ideal gas constant)

or

P*V = n*R*T

The accepted value for R is 8.314472 J/mol*K (Joules per mole per degree Kelvin).

One important result of the Ideal Gas Law is that under constant conditions of pressure and temperature, one mole of any gas will always occupy the same volume. For example, at one atmosphere, the molar volume of an ideal gas would be 22.414 L/mol at 0C and 24.137 L/mol at 21C.

The volume that one mole of an ideal gas occupies when held at a specific temperature and pressure is referred to as a "molar volume". Most gases follow the Ideal Gas Law closely at atmospheric pressure and room temperature.

In this experiment you will determine the molar volume of hydrogen and compare it with the expected ideal gas law value. Hydrogen gas is produced in the reaction:

Zn(s) + 2HCl(aq) -> ZnCl₂(aq) + H₂(g)

It is easy to calculate the number of moles of H₂(g) produced since it is the same as the number of moles of zinc used in the reaction. Knowing the number of moles of H₂(g) produced and measuring the volume that it occupies, one can calculate the molar volume of the gas at room temperature and pressure according to the equation:

Molar volume = measured volume / number of moles (L/mol)

This is the lab procedure

Take an Erlenmeyer flask from the Glassware shelf and place it on the workbench.

2. Add 0.25g of zinc to the Erlenmeyer flask

3. Open the Properties window and click on the Erlenmeyer flask. Click the Open/Close icon in the Properties window to close the flask with an air-tight stopper

4. Take a thermometer and pressure gauge from the Tools shelf and attach them directly to the flask. Record the initial temperature and pressure

5. Add 10 mL of 6M HCl solution to the flask. The HCl is added as if by a syringe piercing the rubber stopper, maintaining the air-tight seal

6. Watch for evidence of the reaction between the zinc and HCl. Record all of the indications that the reaction has occurred

7. The temperature will slowly fall as the flask cools. While you are waiting, take a gas piston from the Glassware shelf and place it on the workbench

8. Once the flask has cooled down to room temperature (21C), disconnect the thermometer and pressure gauge from the flask

9. Drag the flask and drop it onto the gas piston. This connects the two and allows gas to flow from the flask into the gas piston until the pressure equalizes. What pressure is that? If you need to, connect a pressure gauge to the gas piston and measure the pressure inside it

10. Open the Data window, click on the gas piston and record the volume of gas that is contained in the gas piston

11. Repeat the experiment with a new flask and gas piston, using 0.25g of zinc and 20 mL of HCl.
Doc attached. I do not know how to do the calculations.

These are the results of the lab

Add 0.25g Zinc to the Erlenmeyer flask -150mL
Chemicals inside:
1. Zn
2. O2 moles: 0.01243, vol; 149.96mL
3. N2 moles: 0.004972, vol: 149.96mL
Then it is sealed tight with a rubber stopper
Then I take a thermometer and pressure gauge and recorded
Thermometer 21 degrees celsius
Pressure (PSI) 14.697
Then I add 10mL of 6M HCl solution to the flask
And I am spose to record the reaction that takes place
As the temp falls back to 21 degrees Celsius I connect the flask to the gas piston-250mL until the pressure equalizes and what is that pressure.
I then record the volume of gas that is contained in the gas piston and that is
Pressure-gas piston
And the chemicals left inside are
1. O2, moles: 0.000524, vol:102.14mL
2. N2, moles: 0.002096, vol: 102.14mL
3. H2 no data

Then repeat the experiment with a new flask and gas piston using 0.25g of Zinc and 20ml 6M of HCl and after the pressure in the gas piston these are the results
Chemicals left inside of the gas piston
1. O2, moles: 0.001159, Vol; 226.33mL
2. N2, moles: 0.004637 Vol 226.33mL

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