HELP with CHEMISTRY!!!!!?

Question

DATA TABLE

length of Mg ribbon--- .6cm
mass of Mg---.00828g
evidence of chemical reaction--- fizzy, white bubbles
volume of H2 gas---8.4 mL
corrected volume of H2 gas--- 8.2 mL
temperature of water bath--- 21.0C
barometric pressure--- 761.7 mm Hg


1. Calculate teh theoretical number of moles of hydrogen gas produced.


2. I understand this one.


3. Use the combined gas law to convert the measured volume of hydrogen to the volume the gas would occupy at STP.


4. Divide the volume of hydrogen gas at STP by the theoretical number of moles of hydrogen to calculate the molar volume of hydrogen.


5. What is the average value of the molar volume of hydrogen?


6. One mole of hydrogen gas has a mass of 2.02g. Use your value of hte molar volume of hydrogen to calculate the mass of one liter of hydrogen gas at STP. Thes is the density of hydrogen in g/L. How does this experimental value of the density compare with th

Answer 1

This is a mass - volume stoichiometry problem.

Here are the basics. You will need to do the detailed work

Set up a balanced equation between Mg and an acid. Use HCl, it is easier. The reaction will generate H2 gas.

The length of Mg is irrelevent, it is only the mass that counts. Convert the grams to moles and use tthe mole ratio to calculate moles of H2. That's #1

Adjust the gas collected at 21 oC and 761.7 mm to STP, i.e 0 oC and 760 mm. Don't forget to use Kelvin and not oC. That's #3

Use the above and the answer to #1 for question #4

I'm not sure what #5 is asking. Something is missing

For #6, use the ideal gas law PV = nRT. Substitute STP conditions and 1 liter for V. Solve for N = moles. Use 2.02g molecular mass to calculate grams in 1 liter.

Simpler way is to divide 1/22.4 and multiply by 2.02

Answer 2

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