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Moles II – Stoichiometry

Question 1

Given the chemical equation

Na(s) + H2O(ℓ) → NaOH(aq) + H2(g)

  1. a)  Balance the equation.
  2. b)  How many molecules of H2are produced when 332 atoms of Na react?

 

Question 2

Given the chemical equation

S(s) + O2(g) → SO3(g)

  1. a)  Balance the equation.
  2. b)  How many molecules of O2are needed when 38 atoms of S react?

 

Question 3

For the balanced chemical equation

6 H+(aq) + 2 MnO4−(aq) + 5 H2O2(ℓ) → 2 Mn2+(aq) + 5 O2(g) + 8 H2O(ℓ)

how many molecules of H2O are produced when 75 molecules of H2O2 react?

 

Question 4

For the balanced chemical reaction

2 C6H6(ℓ) + 15 O2(g) → 12 CO2(g) + 6 H2O(ℓ)

how many molecules of CO2 are produced when 56 molecules of C6H6 react?

 

Question 5

Given the balanced chemical equation

Fe2O3(s) + 3SO3(g) → Fe2(SO4)3

how many molecules of Fe2(SO4)3 are produced if 321 atoms of S are reacted?

 

Question 6

For the balanced chemical equation

CuO(s) + H2(g) → Cu(s)  + H2O(ℓ)

how many moles of CuS are formed if 2g of H2 react?

 

Question 7

For the balanced chemical equation

Fe2O3(s) + 3 SO3(g) → Fe2(SO4)3

suppose we need to make 145,000 molecules of Fe2(SO4)3. How many molecules of SO3 do we need?

 

Question 8

One way to make sulfur hexafluoride is to react thioformaldehyde, CH2S, with elemental fluorine:

CH2S + 6 F2 → CF4 + 2 HF + SF6

If 45,750 molecules of SF6 are needed, how many molecules of F2 are required?