A 40.0 g sample of zinc is allowed to react with excess hydrochloric acid. How many liters of dry hydrogen gas are produced if the gas is collected over water at 23.0 degrees celsius and 1.234 atm of pressure? (Vapor pressure of water at 23.0 degrees celsius is 21.0 mmHg)

Correct me if I am wrong, but I thought I should use D=(PxM)/nRT to find the space hydrogen gas occupies and then find the liters of dry hydrogen gas produced with V=nRT/P. Is this the right process?

Is D density?

Zn + 2HCl ==> ZnCl2 + H2
Calculate mols Zn and convert to mols H2.
Then use PV = nRT
P will be 1.234 atm - vp H2O (in atm)[or convert 1.234 atm to mm Hg and use 21.0 mm for vp H2O)
Everything else is as usual and V will be ihn liters.

Yes, you're on the right track! The ideal gas law equation, PV = nRT, can be used to solve this problem. Let's break down the steps.

Step 1: Convert the pressure of the gas to the same units.

In this case, the given pressure is 1.234 atm. The vapor pressure of water at 23.0 degrees celsius is also given as 21.0 mmHg. We need to convert this to atm, since the rest of the values are in atm.

To convert 21.0 mmHg to atm, divide by 760 (since there are 760 mmHg in 1 atm).

21.0 mmHg / 760 mmHg/atm = 0.0276 atm

Therefore, the total pressure is 1.234 atm + 0.0276 atm = 1.2616 atm.

Step 2: Calculate the number of moles of hydrogen gas.

Since the reaction is between zinc and hydrochloric acid, it produces hydrogen gas. To find the number of moles, we need to use the stoichiometry of the reaction. The balanced equation for the reaction is:

Zn + 2HCl -> ZnCl2 + H2

This tells us that for every 1 mole of zinc, we get 1 mole of hydrogen gas. So, the number of moles of hydrogen gas produced is the same as the number of moles of zinc used.

Given that you have a 40.0 g sample of zinc, you can convert this mass to moles using the molar mass of zinc (65.38 g/mol).

40.0 g Zn * (1 mol Zn / 65.38 g Zn) = 0.6129 mol Zn (rounded to 4 decimal places)

Therefore, you have 0.6129 mol of hydrogen gas.

Step 3: Calculate the volume of the hydrogen gas.

Now, you can use the ideal gas law equation, V = nRT/P, to find the volume of the hydrogen gas.

V = (0.6129 mol * 0.0821 L*atm/mol*K * 296.15 K) / 1.2616 atm

= 0.428 L

Therefore, approximately 0.428 liters of dry hydrogen gas are produced.

Remember to always convert the units properly and use accurate values to get the correct answer.