The problems:

0.0513 grams of Al (Wt. 27.0) was reacted with excess HCI to produce H2 according to the following balanced equation:

2 Al + 6 HCI ---> 2 AlCl3 + 3 H2

a) Determine the number of moles of H2 evolved from that quantity of Al when collected over water?

0.0513g Al x 1 mol Al / 27g Al x 3 mol H2 / 2 Mol Al = 0.00285 mol H2

b) If the volume of gas generated was 75mL and the temp was 27°C , determine the total pressure of the hydrogen gas evolved from the quantity of Al stated above?

PV=nRT --> P = nRT/V

(0.00285)(0.082)(300) / 0.075 = 0.9348

c) The vapor pressure of water at 27°C was 26.7 mmHg, determine the partial pressure of the hydrogen gas collected in mmHg?

And this one I cant find an example in my book so I don't know which formula to follow.

To determine the partial pressure of the hydrogen gas collected in mmHg, you can use Dalton's Law of Partial Pressures. According to Dalton's Law, the total pressure of a mixture of gases is equal to the sum of the partial pressures of each gas in the mixture. In this case, the mixture consists of hydrogen gas (H2) and water vapor.

The partial pressure of the hydrogen gas is equal to the total pressure of the gas mixture (determined in part b) minus the vapor pressure of water at the given temperature (27°C, with a vapor pressure of 26.7 mmHg).

Partial pressure of hydrogen gas = Total pressure - Vapor pressure of water

Partial pressure of hydrogen gas = 0.9348 atm (from part b) - 26.7 mmHg (vapor pressure of water)

However, for accurate calculations, we need to convert the vapor pressure of water from mmHg to atm.

To convert mmHg to atm, we use the conversion factor: 1 atm = 760 mmHg.

So, vapor pressure of water in atm = 26.7 mmHg / 760 mmHg/atm

Now you can subtract the vapor pressure of water in atm from the total pressure to find the partial pressure of the hydrogen gas in atm.

Partial pressure of hydrogen gas = 0.9348 atm - (26.7 mmHg / 760 mmHg/atm)

Finally, you can convert the partial pressure of the hydrogen gas back to mmHg by multiplying by 760 mmHg/atm.

Partial pressure of hydrogen gas in mmHg = (Partial pressure of hydrogen gas) * 760 mmHg/atm

I hope this helps! Let me know if you have any further questions.

To determine the partial pressure of the hydrogen gas collected in mmHg, you can use Dalton's Law of Partial Pressures. According to Dalton's Law, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of each individual gas.

In this case, the total pressure is the sum of the vapor pressure of water and the partial pressure of hydrogen gas. The vapor pressure of water is given as 26.7 mmHg.

To find the partial pressure of the hydrogen gas, subtract the vapor pressure of water from the total pressure.

Partial pressure of hydrogen gas = Total pressure - Vapor pressure of water
= 0.9348 atm - 26.7 mmHg

Note that you need to convert the total pressure from atm to mmHg, as the vapor pressure is given in mmHg.

To convert atm to mmHg, you can use the conversion factor 1 atm = 760 mmHg.

So, 0.9348 atm = 0.9348 x 760 mmHg = 710.208 mmHg.

Now, you can calculate:

Partial pressure of hydrogen gas = 710.208 mmHg - 26.7 mmHg
= 683.508 mmHg

Therefore, the partial pressure of the hydrogen gas collected is 683.508 mmHg.