Theoretical yield and other chemistry problems

Question

1. What is the theoretical yield of Cr (chromium)that can be produced by the reaction of 40.0g of Cr2O3 with 8.00g of Al according to the equation:

2Al Cr2O3 ------> Al2O3 2Cr

a. 7.7g b. 15.4g c. 27.3g d. 30.8g e. 49.9g

2. What is the maximum number of grams of Ammonia (NH3) that can be obtained from the reaction of 10.0g H2 and 80.0g N2?

N2 3H2 ------> 2NH3

a. 28.4g b. 48.6g c. 56.7g d. 90.0g e. 97.1g

3. HCl can be prepared by the ff reaction:

2NaCl H2SO4 -- 2HCl Na2SO4

How many grams of HCl can be prepared from 2.00mol H2SO4 and 150g NaCl?

a. 7.30g b. 93.5g c. 146g d. 150g e. 196g

4. Calculate the mass of FeS formed when 9.42g of Fe reacts with 8.50g of S.

Fe S ----> FeS

a. 17.9g b. 87.9g c. 26.0g d. 14.8g e. 1.91 x 10^ -3 g

pleas show all solutions, need help badly, i already consulted my chemistry books but there were no problems like those. thanks!

Answer 1

This smells of you not having tried the work. Why else would you list them all as one?

It's pretty easy. Use the molar masses. You have the stoichiometry right there.