Question

Q1 How many moles of CS2 form when 3.4 moles of carbon react with excess sulfur dioxide?

C(S) + SO2 (g) CS2 (l) + CO(g)



q 2If you have 66.6 g of NH3, how many grams of HF will be produced?

F2 (g) + NH3 (g) N2F4 (g) + HF(g)


q 3 Based on your answer to question #2, What would your percent yield be if you actually produced 177.2 g of HF?

q4 How many molecules of N2 form when 1055 g of N2H4 reacts with excess O2?

N2H4 (l) + O2 (g) N2 (g) + H2O (g)

q 5 How many grams of NH4NO3 will be formed when 15.3 g of nitrogen gas are combined with 12.7 g of oxygen gas?

2N2 (g) + 4 H2O (g) + O2 (g) 2 NH4NO3 (s)

q 6 What is the limiting reactant in question #5?

Answer 1

q1 When 3.4 moles of carbon react with excess sulfur dioxide, 1 mole of carbon would react with 2 moles of SO2 to form 1 mole of CS2.

So 3.4 moles of C would react with 2 * 3.4 = 6.8 moles of SO2 to form 3.4 moles of CS2.

q2 With 66.6 g of NH3,

F2 (g) + NH3 (g) N2F4 (g) + HF(g)

2 moles of F2 would react with 1 mole of NH3.

So 66.6 g NH3 would react with 2 * (34 g/mole F2 ) = 68 g F2

producing 68 g HF

q3 If you produced 177.2 g of HF, the percent yield would be

(Actual yield HF / Theoretical yield HF) * 100%

= (177.2 g / 68 g) * 100% = 260%

q4 When 1055 g of N2H4 reacts with excess O2,

1055 g N2H4 would contain 1055 / 28 = 37.5 moles of N2H4.

Since 1 mole of N2H4 produces 1 mole of N2 and 2 moles of H2O,

37.5 moles of N2H4 would produce 37.5 moles of N2 gas.

q5 When 15.3 g of N2 and 12.7 g of O2 are combined,

15.3 g N2 would be 15.3 / 28 = 0.545 moles N2

12.7 g O2 would be 12.7 / 32 = 0.396 moles O2

2N2 (g) + 4 H2O (g) + O2 (g) 2 NH4NO3 (s)

For each 2 moles N2 and 1 mole O2, 2 moles NH4NO3 are formed.

So with 0.545 moles N2 and 0.396 moles O2, 0.272 moles NH4NO3 can be formed.

Given the molar mass of NH4NO3 is 80 g/mole, this would be 0.272 moles * 80 g/mole = 21.76 g NH4NO3

q6 From the amounts given, 0.272 moles NH4NO3 can be formed.

You have 0.545 moles N2 available which can produce 0.272 moles NH4NO3.

So N2 is the limiting reactant.