Chemical Reactions Test Correctives

Skill 1: Pages 169-173, 182-184, 191-194 in online textbook

  1. Define law of conservation of matter, reactant, product, endothermic, and exothermic.
  2. Which of the following must be the same on both sides of a balanced chemical equation?

a. number of moleculesd. number of different phases

b. number of atomse. number of moles

c. total atomic massf. number of ions

3. A student adds 45.0 grams of solid sodium to a container of chlorine gas and 52.0 grams of

solid sodium chlorine are formed. How many grams of chlorine gas were in the container to

start?

  1. On which side of the following equation would you write the word heat? Explain.

H2O(s)  H2O(g)

  1. What is the difference between NaCl(aq) and NaCl(l)?
  2. If a piece of blackboard chalk is heated strongly, the mass of the chalk decreases substantially, and the chalk is converted to a fine powder. What evidence is there for a chemical reaction having taken place?

Skill 2: Pages 175-178 in online textbook

  1. Define coefficient, aqueous, and diatomic molecule.
  2. Why must a chemical equation be properly balanced by putting numbers (coefficients) in front of the molecules instead of as a subscript after an atom in a molecule?
  3. Balance the following reactions:
  1. SiI4(s) + Mg(s) Si(s) + MgI2(s)
  2. Ba(s) + S8(s)  BaS(s)
  3. PbCl2(aq) + K2SO4(aq)  PbSO4(s) + KCl(aq)
  4. CaC2(s) + H2O(l)  Ca(OH)2(s) + C2H2(g)
  1. If aqueous solutions of potassium chromate and barium chloride are mixed, a bright yellow solid (barium chromate) forms and settles out of the mixture, leaving potassium chloride dissolved in an aqueous solution as the other product. Write a balanced chemical equation for this process.

Skill 3:

  1. Define ion exchange reaction.
  2. Do problem 33 on page 247 describing the reactions as either synthesis, decomposition, single replacement or double replacement.
  3. Identify the type of the reaction and write a balanced formula equation for each of the following.
  4. calcium carbonate  calcium oxide + carbon dioxide
  5. potassium bromide + chlorine  potassium chloride + bromine
  6. tin + oxygen  tin (IV) oxide
  7. zinc nitrate + hydrogen sulfide  zinc sulfide + nitric acid

Helpful video links are on the next page.

Skill 4: See video on predicting products in chemical reactions.

  1. Define precipitate and analysis reaction.
  2. In order for a double replacement reaction to occur what phase of matter must be formed?
  3. In order for a single replacement reaction to occur does the element that is on its own have to be more reactive or less reactive than the element it is replacing in the compound?
  4. Complete and balance the following incomplete reactions. Show the phases for reaction e.

a. H2 + ?  H2Od. NO2  ? + O2

b. Ca + Cl2  ?e. CaCl2 + AgNO3  ? + ?

c. ? + Al(OH)3  Al + Ca(OH)2

  1. What phase notation is used to show a precipitate?

6. Write a balanced chemical equation for the reaction that occurs when aqueous sodium

hydroxide is mixed with aqueous magnesium nitrate. Be sure to include the phases of the

products.

Helpful Videos

- shows the molecules in addition to the formulas

- Video that includes reactions with polyatomic ions.

- link to practice balancing equations with ways to check answers and get hints.

- Video on predicting products in chemical reactions.