Chapter 6

 

Matching

 

Match each item with the correct statement below.

a.	activation energy	i.	equilibrium
b.	catalyst	j.	inhibitor
c.	chemical reaction	k.	insoluble
d.	coefficient	l.	product
e.	combustion	m.	reactant
f.	concentration	n.	single-displacement
g.	decomposition	o.	soluble
h.	enzymes	p.	synthesis

 

 

____          1.   The replacement of hydrogen from water by sodium is an example of a(n) _____ reaction.

 

____          2.   In order to balance a chemical equation, it may be necessary to add a(n) _____ before one or more of the symbols or formulas.

 

____          3.   _____ is a type of chemical reaction in which a substance combines rapidly with oxygen to form oxides.

 

____          4.   A(n) _____ is any substance that produces other substances in a chemical reaction.

 

____          5.   Chemists often add a(n) _____ to a reaction if they want to increase the rate at which the reaction is taking place.

 

____          6.   The human body contains _____, which are catalysts that change the rates of biochemical reactions.

 

____          7.   You can slow down a chemical reaction by adding a(n) _____ to the reaction.

 

____          8.   The carbon dioxide formed when coal burns is a(n) _____ of that reaction because it is formed as a result of the reaction.

 

Match each statement with the correct item below.

a.	2Na + Cl2 ® 2NaCl
b.	burning of coal in oxygen
c.	an amount of reactant present in a small enough amount to determine when the reaction will stop
d.	NaCl in 2Na + Cl2 ® 2NaCl
e.	substance that slows down a reaction
f.	energy required to get a reaction started
g.	Cl2 + 2NaBr ® Br2 + 2NaCl
h.	the 2 in 2NaCl
i.	substance that speeds up a reaction without being used up
j.	any chemical change
k.	2KBr + Pb(NO3)2 ® 2KNO3 + PbBr2
l.	substance that appears as a precipitate
m.	rate of A + B ® AB equals rate of AB ® A + B
n.	either Na or Cl2 in 2Na + Cl2 ® 2NaCl
o.	Ca(OH)2 ® CaO + 2H2O

 

 

____          9.   double displacement

 

____          10.  coefficient

 

____          11.  synthesis

 

____          12.  dynamic equilibrium

 

____          13.  activation energy

 

____          14.  combustion

 

____          15.  reactant

 

____          16.  single displacement

 

Short Answer

 

                  17.  Wood can burn, but large piles of timber in a lumberyard do not catch fire on their own, even though they are surrounded by oxygen in the air. Why?

 

                  18.  In the equation 2K(s) + 2H₂O(l) ® 2KOH(aq) + H₂(g), what is the physical state of each reactant and product?

 

                  19.  Write a balanced chemical equation for the reaction described:

aluminum metal + hydrochloric acid ® aluminum chloride solution + hydrogen.

 

                  20.  Balance the equation Sr(s) + H₂O(l) ® Sr(OH)₂(aq) + H₂(g).

 

                  21.  Classify the reaction, NH₄HS(s) ® NH₃(g) + H₂S(g), as either decomposition, single displacement, combustion, synthesis, or double displacement.

 

                  22.  Lithium metal reacts with ammonia gas to form hydrogen gas and crystals of lithium amide, LiNH₂. Write a balanced chemical equation for this reaction, and classify the reaction as one of the five major types.

 

                  23.  When an aqueous solution of lead(II) nitrate is combined with an aqueous solution of sodium sulfate, a white precipitate of lead(II) sulfate forms. Write word and balanced chemical equations for this reaction.

 

                  24.  Sodium metal will combine with oxygen in dry air to form solid sodium oxide. Write a balanced chemical equation for this reaction. If 90 trillion sodium atoms and 30 trillion oxygen molecules are available to react, which is the limiting reactant?

 

                  25.  Suppose that the reversible reaction represented by the equation 2SO₂(g) + O₂(g)  2SO₃(g) has come to equilibrium. If a catalyst is added to the equilibrium mixture, will the reaction shift to the left or to the right?

 

                  26.  The graph shown in Figure 6-2 represents the concentrations of three compounds, A, B, and C, as they take part in a reaction that reaches equilibrium. Which compound(s) represent the reactant(s) and product(s) in this reaction?

 

 

Problem

 

A series of eight test tubes is lined up on top of a laboratory bench. The contents of these test tubes are listed. The contents are exposed to O₂ in the air. Water or energy may be added to the contents, if necessary, for reaction to occur. Predict the type of chemical reaction that is most likely to take place in each of the eight test tubes. If no reaction will take place, explain why. Give a balanced chemical equation for each reaction that takes place.

 

                  27.  zinc metal:

 

                  28.  magnesium metal and iron(III) chloride:

 

                  29.  barium chloride and potassium sulfate:

 

                  30.  sodium oxide:

 

Sulfur dioxide gas (SO₂) reacts with oxygen to form sulfur trioxide gas (SO₃). The graph in Figure 6-1 shows how the concentration of these three gases changes over time in an experiment in which first the concentration of only the sulfur dioxide is increased, and then the concentration of only the oxygen is increased. Answer the following questions relating to this graph.

 

 

                  31.  At approximately what time was the concentration of sulfur dioxide increased?