K4: K-4 W/UNIT K STUDY GUIDE

K-4 WRITTEN—STOICHIOMETRY PRACTICE PROBLEMS

  1. Bromine liquid (Br2) reacts with aqueous sodium iodide (NaI) in a single replacement reaction to produce aqueous sodium bromide (NaBr) and solid iodine crystals (I2).

a)Write the balanced reaction equation.

b)How many moles of sodium bromide could be produced from 0.172 moles of bromine liquid?

  1. Calculate the volume occupied by 16.3 moles of nitrogen gas at 273 K and 101.3 kPa.
  2. How many moles of fluorine gas, F2, are contained in a 0.269 dm3 container at STP?
  3. Diatomic oxygen gas reacts with diatomic nitrogen gas to yield nitrogen dioxide gas.

a)Write the balanced reaction equation.

b)Assuming that all gases are at STP, find the volume of nitrogen dioxide gas that could be produced from 71.11 dm3 of diatomic nitrogen gas.

  1. Diatomic oxygen gas reacts with calcium metal to form calcium oxide solid (CaO).

a)Write the balanced reaction equation.

b)How many formula units of CaO can be produced from 4.9105molecules of diatomic oxygen gas?

  1. Given the balanced chemical equation for the decomposition of phosphorus oxyfluoride gas (POF3),

4POF3 (g)  P4 (s) + 2O2 (g) + 6F2 (g)

What volume, at STP, of fluorine gas (F2) would be produced by the decomposition of 9.221025 molecules of phosphorus oxyfluoride?

  1. Calculate the mass of mercury metal (Hg) that is required to produce 39.8 g of mercury (I) oxide (Hg2O) according to the following balanced chemical reaction equation.

4Hg (l) + O2 (g)  2 Hg2O (s)

  1. Find the number of grams of sulfur (S) that is produced when 1.87 dm3 of oxygen gas (O2) at STP is also produced by the decomposition of sulfur trioxide gas (SO3) according to this balanced chemical equation:

2SO3 (g)  2S(s) + 3O2 (g)

  1. Sodium chloride (NaCl) is produced when sodium metal (Na) is reacted with diatomic chlorine gas (Cl2)

a)Write the balanced chemical equation.

b)How many formula units of sodium chloride (NaCl) are produced by the reaction of 40.3 grams of diatomic chlorine (Cl2) gas?

  1. Sodium reacts with water to from sodium hydroxide and hydrogen gas:

2Na (s) + 2H2O (l)  2NaOH (aq) + H2 (g)

a)If 90.0 g of sodium is dropped into 80.0 g of water, which reactant is in excess, and how much is left over?

b)What volume of H2 at STP would be produced from the above amounts of reactants (remember to use the limiting reactant as the basis for your calculations)?

  1. Phosphorus burns in oxygen gas to produce phosphorus (V) oxide (P4O10):

P4 (s) + 5O2 (g)  P4O10 (g)

a)If 2.50 g P4 is ignited in a flask with 0.75 dm3 O2 at STP, which reactant is in excess, and how much is left over?

b)How many grams of P4O10 are formed (remember to use the limiting reactant as your basis)?

UNIT K STUDY GUIDE

VOCABULARY/CONCEPTS

As mentioned in the unit outline, you must be able to define and apply your understanding of the following terms:

K1-1 / composition stoichiometry and reaction stoichiometry (9-1)
K1-2 / types of reaction stoichiometry problems (9-1)
K1-3 / Avogadro’s Hypothesis (Law) (12-2)
K1-4 / STP (12-2)
K1-5 / molar volume of gases (12-2)
K1-6 / what coefficients can represent (mole ratios, volume ratios, molecule ratios) (9-1, unit notes)
K1-7 / volume—volume problems (unit notes)
K1-8 / stoichiometry using a recipe (unit notes)
K2-1 / procedure for solving mass—mass problems (9-1, unit notes)
K2-2 / procedure for solving mixed mass—volume—particle problems (9-1, unit notes)
K3-1 / limiting and excess reactants (9-2)
K3-2 / reasons for using excess reactants in real life (9-2)
K3-3 / determining the limiting reactant, and calculating product yields(9-2)
K3-4 / percent yield (9-2)

It is likely that questions concerning vocabulary will take the form of multiple choice or matching questions.

In the open response section, you should be able to do the following:

  1. list what information can derived from the coefficients of a balanced equation (moles, molecules/particles, liters, etc.),
  2. determine the number of moles, molecules/particles, and liters represented by the coefficients of a balanced equation,
  3. convert the number of moles of a substance intosample mass,
  4. convert the number of moles of a substance into molecules/particles,
  5. convert the number of moles of a substance into liters,
  6. use stoichiometric analysis and dimensional analysis (factor label method) to solve problems involving the calculation of the mass, moles, particles and/or liters of a product given quantitative information about a reactant,
  7. use stoichiometric analysis and dimensional analysis (factor label method) to solve problems involving the calculation of the mass, moles, particles and/or volume (in dm3) of a product given quantitative information about a product.
  8. Given a balanced chemical reaction equation and starting reactant quantities, be able to determine which reactant limits (or is in excess), and determine the quantities of products produced, and how much excess reactant remains at the end of the reaction.
  9. Once a theoretical yield has been determined, use this information and actual yield information to calculate percent yield for a reaction.