Can someone please help me?

Question

Using the balanced chemical equation: 

H₂ + Cl₂ → 2HCl

How many grams of hydrochloric acid (HCl) are produced from 2.7 g of chlorine (Cl2) reacting with excess hydrogen?

 

Answer 1

This is exactly like the other question you posted. The only difference is in this question you have 2.7 g of Cl₂ and excess H₂.

H₂ + Cl₂ ==> 2HCl ... balanced equation

Since H₂ is present in excess, the final amount of HCl is dictated by the amount (moles) of Cl₂ present. Again, as before, always work in moles until the end, and then convert back to grams.

moles Cl₂ present = 2.7 g Cl₂ x 1 mole Cl₂ / 70.9 g Cl₂ = 0.03808 moles Cl₂ present

Now use the balanced equation to find moles of HCl produced:

moles HCl produced = 0.03808 moles Cl₂ x 2 moles HCl / 1 mole Cl₂ = 0.0762 moles of HCl produced

Finally, convert this to grams of HCl produced:

0.0762 moles HCl x 36.46 g HCl / mole HCl = 2.777 g HCl

Rounding this answer to 2 significant figures (based on 2 s.f. in 2.7 g Cl₂), we get

2.8 g HCl produced

Answer 2

Hello, thank you for taking the time to post your question!

I would start by converting the grams of Cl2 over into moles, that means taking

2.7 g / 70.90 g/mol = 0.0381 mol of Cl2

The next step then is converting that over into mol of HCl, you can find that by multiplying

0.0381 mol Cl2 x 2 mol HCl / 1 mol Cl2 = 0.0762 mol of HCl

The final step then is to multiply by the molar mas of HCL to convert over into grams

0.0762 mol of HCl x 36.46 g/mol = 2.78 g of HCl

So a mass of 2.78 g of HCl is produced from 2.7 g of CL2 reacting with excess hydrogen

I hope that helps you get moving in a better direction on this type of question! Feel free to reach out if you have any additional questions beyond that :)