Chapter 15 Holt
Chemical Reactions
Using Vocabulary
• 1. Adding a(n) inhibitor will slow down a
chemical reactions.
• 2. A chemical reaction that gives off light
is called exothermic.
• 3. A chemical reaction that forms one
compound from two or more substances
is called a synthesis reaction.
• 4. The 2 in the formula Ag2S is a
subscript.
• 5. The staring materials in a chemical
reaction are reactants.
Understanding Concepts
• 6. Balancing a chemical equation so
that the same number of atoms of each
element is found in both the reactants
and the products is an illustration of
• C) the law of conservations of mass.
• 7. What is the correct chemical formula
for calcium chloride?
• B) CaCl2
• Ca has a valence of 2, so 2+ charge
• Cl has a valence of 7, so -1 charge
• So 2 Cl- with Ca++ makes CaCl2
• 8. In which type of reaction do ions in
two compounds switch places?
• D) double-replacement
• Ex: NaOH + HCl --> NaCl + H2O
• 9. Which is an example of the use of
activation energy?
• C) holding a match to paper
• 10. Enzymes in your body act as
catalysts. The role of enzymes is to
• A) Increase the rate of chemical
reactions (make the reactions happen
faster)
Short Answers
• 11. Classify each of the following
reactions:
• A) Fe + O2 --> Fe2O3 synthesis
• Balanced this would be
• 4Fe + 3O2 --> 2Fe2O3
• Iron + oxygen --> rust
•
•
•
•
•
B) Al + CuSO4 --> Al2(SO4)3 + Cu
single replacement
Balanced this is
2Al + 3CuSO4 --> Al2(SO4)3 + 3Cu
Aluminum + cupric sulfide --> aluminum
sulfide plus copper
• C) Ba(CN)2 + H2SO4 --> BaSO4 +HCN
• Double replacement
• Balanced this is
• Ba(CN)2 + H2SO4 --> BaSO4 + 2HCN
• 12. Name two ways that you could
increase the rate of a chemical reaction.
• 1) raise the temperature
• ( this increases the concentration and/or
the surface area)
• 2) add a catalyst
• 13. The reactants are acetic acid
(vinegar) and baking soda (sodium
bicarbonate).
• The products are carbon dioxide CO2 ,
water H2O, and sodium acetate.
•
•
•
•
•
•
•
14. Concept map is on the white board.
Terms are:
Chemical reaction
Chemical equation
Chemical formulas
Reactants, products,
Coefficients, subscripts
Critical Thinking & Problem
Solving
• 15. Your friend is very worried by
rumors he has heard about a substance
called dihydrogen monoxide. What
could you say to your friend to calm his
fears?
• Dihydrogen H2
• Monoxide O
• So H2O - not to worry - its water !
• 16.
As long as proper safety
precautions have been taken, why can
explosives be transported long
distances without exploding?
• Explosives need to absorb energy to
being the reaction. Without this
absorption, they can be transported
safely.
Math in Science
• 17. Calculate the number of atoms of
each element shown in each of the
following:
• A) CaSO4
• Ca - Calcium - 1 atom
• S - Sulfur - 1 atom
• O - Oxygen - 4 atoms
•
•
•
•
B) 4NaOCl
Na - sodium - 4 atoms
O - oxygen - 4 atoms
Cl - chlorine - 4 atoms
•
•
•
•
C) Fe(NO3)2
Fe - iron - 1 atom
N - nitrogen - 2 atoms
O - oxygen - 6 atoms
• D) 2Al2(CO3)3
• Al - Aluminum - 4 atoms
• C - carbon - 6 atoms
• O - oxygen - 18 atoms
• 18. Write balanced equations for the
following:
• A) Fe + O2 --> Fe2O3
• 18. Write balanced equations for the
following:
• A) Fe + O2 --> Fe2O3
• Answer:
• 4Fe + 3O2 --> 2 Fe2O3
• B) Al + CuSO4 --> Al2(SO4)3 + Cu
• Answer
• B) Al + CuSO4 --> Al2(SO4)3 + Cu
• Answer
• 2Al + 3CuSO4 --> Al2(SO4)3 + 3Cu
• C)
• Ba(CN)2 + H2SO4 --> BaSO4 + HCN
• C)
• Ba(CN)2 + H2SO4 --> BaSO4 + HCN
• Answer
• Ba(CN)2 + H2SO4 --> BaSO4 + 2HCN
• 19) Balanced chemical equations:
• A) bromine reacts with sodium iodide to
form iodine and sodium bromide
• Br2 + 2NaI --> I2 + 2NaBr
• B) Phosphorus reacts with oxygen gas
to form diphosphorus pentoxide
• 4P + 5O2 --> 2P2O5
• C) Lithium oxide decomposes to form
lithium and oxygen
• 2Li2O --> 4Li + O2
Interpreting Graphics
• 20. In the photo on page 393, what
evidence supports that this is a
chemical reaction?
• Answer
• - Bubbles of gas are produced
• - Light is given off
• 21. Using the energy diagram on page 393,
answer q’s a,b,c
• A) “C” represents the energy of the products
(far right section of graph)
• B) “B” represents the activation energy of the
reaction (increases then peaks)
• C) Energy is “given off” by this reaction.
•
That’s the decline of energy below starting
energy mark - “D” on the chart)