Chemical equations and stoichiometry

Question 1 of 10

Sodium hydroxide reacts with hydrochloric acid: NaOH + HCl → NaCl + H₂O. A student neutralised 4 g of sodium hydroxide with excess acid and obtained 5.27 g of dry sodium chloride. (Na = 23, O = 16, H = 1, Cl = 35.5) Calculate (a) the moles of NaOH used, (b) the theoretical mass of NaCl, (c) the percentage yield. (d) Give one reason why the yield is less than 100%.

Question 2 of 10

What volume of hydrogen at s.t.p. is produced when 13 g of zinc reacts with excess hydrochloric acid? Zn + 2HCl → ZnCl₂ + H₂ (Zn = 65, molar volume 22.4 dm³)

Question 3 of 10

The number of atoms of each element is the same on both sides of a balanced equation.

Question 4 of 10

Balance: __H₂ + __O₂ → __H₂O

Question 5 of 10

What mass of magnesium oxide is produced when 4.8 g of magnesium burns completely? 2Mg + O₂ → 2MgO (Mg = 24, O = 16)

Question 6 of 10

What mass of calcium oxide is formed when 20 g of calcium carbonate is heated completely? CaCO₃ → CaO + CO₂ (Ca = 40, C = 12, O = 16)

Question 7 of 10

Balance: __Al + __O₂ → __Al₂O₃

Question 8 of 10

Sodium hydroxide reacts with hydrochloric acid: NaOH + HCl → NaCl + H₂O. A student neutralised 20 g of sodium hydroxide with excess acid and obtained 23.4 g of dry sodium chloride. (Na = 23, O = 16, H = 1, Cl = 35.5) Calculate (a) the moles of NaOH used, (b) the theoretical mass of NaCl, (c) the percentage yield. (d) Give one reason why the yield is less than 100%.

Question 9 of 10

What volume of hydrogen at s.t.p. is produced when 3.25 g of zinc reacts with excess hydrochloric acid? Zn + 2HCl → ZnCl₂ + H₂ (Zn = 65, molar volume 22.4 dm³)

Question 10 of 10

In N₂ + 3H₂ → 2NH₃, 3 mol of nitrogen reacts completely to give ___ mol of ammonia.