Working with dalton's laws

[jackjones12]

Homework Statement

Given the following chemical reaction:
Zn + HCl ----> ZnCl₂ + H₂(g)

If you measured the total volume of collected gas over water at 20 Celsius to be 428 ml at a total pressure of 845 torr, how many milliliters of 2.6M HCl would be required to produce the correct amount of Hydrogen?

Homework Equations

Dalton's Laws

The Attempt at a Solution

Im not asking for a complete answer here just need help starting, I can't seem to even get how to begin this problem. Any information will be appreciated, thanks.

 

[Borek]

How many moles of gas were collected?

Can you use this number of moles to calculate moles of HCl necessary? Then volume of solution that contains these moles?

 

[jackjones12]

How can i find out how many moles I collected if i wasnt even given how many i started of with. I am sorry to sound dumb but I am having a difficult with this. It might be that I am just missing something really small.

 

[Borek]

You are missing something something really big. It is called ideal gas equation.

 

[DeeNos]

To begin, we need to understand what Dalton's Laws are and how they apply to this problem. Dalton's Laws state that in a mixture of gases, the total pressure is equal to the sum of the partial pressures of each individual gas. In this case, the mixture of gases is the hydrogen gas (H2) and the water vapor (H2O) produced in the chemical reaction.

We also need to know the molar ratio of the reactants in the chemical reaction. From the balanced equation, we can see that for every 1 mole of zinc (Zn) reacted, 2 moles of hydrogen gas (H2) are produced. This means that the amount of hydrogen gas produced is directly proportional to the amount of zinc reacted.

Now, let's look at the information given in the problem. We know that the total volume of gas collected is 428 ml and the total pressure is 845 torr. Using Dalton's Laws, we can calculate the partial pressure of hydrogen gas in the mixture by subtracting the partial pressure of water vapor from the total pressure. We can then use the ideal gas law (PV = nRT) to calculate the moles of hydrogen gas produced.

Next, we need to determine the moles of zinc reacted in order to produce the calculated amount of hydrogen gas. This can be done by using the molar ratio from the balanced equation.

Finally, we can use the molarity of the HCl solution (2.6M) and the moles of zinc reacted to calculate the volume of HCl needed to produce the correct amount of hydrogen gas.

I hope this helps you get started on the problem. Remember to always think about the relevant equations and concepts when approaching a scientific problem. Good luck!