Download Chemical Reactions

Name__________________________________Period_______Date_________
Chemical Reactions
Directions: Read 260-267 in your textbook, and then answer the following questions:
1. List four observations that indicate that a chemical reaction may be taking place.
2. List the three requirements for a correctly written chemical equation.
3. List the seven elements that normally exist as diatomic molecules.
4. a. What is meant by the term coefficient in relation to a chemical equation?
b. How does the presence of a coefficient affect the number of atoms of each
type in the formula that the coefficient precedes?
5. In each of the following formulas, write the total number of atoms present.
________________ a. 4SO2
________________ b 8O2
________________ c. 3Al2(SO4)3
6. Match the symbol on the left with its appropriate description on the right.
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_____ 
(a) A precipitate forms.
_____ 
(b) A gas forms.
_____ 
(c) A reversible reaction occurs.
_____ (l)
(d) Heat is applied to the reactants.
_____ (aq)
(e) A chemical is dissolved in water.
_____


(f) A chemical is in the liquid state.
_____ 7. Which of the following is true regarding the law of conservation of mass?
a. It dictates that the number of molecules on each side of a chemical
equation must be the same.
b. It dictates that the number of atoms of each element must be the same on
both sides of a chemical equation.
c. It states that the mass of the reactants must remain constant in order for a
chemical reaction to proceed.
d. It does not apply to chemical reactions.
_____ 8. Which of the following may indicate that a chemical reaction has occurred?
a. release of energy as light
b. a color change
c. gas bubble formation
d. All of the above
_____ 9. Which of the following is a product in the reaction described by the word
equation: iron + copper(II) sulfate → iron(II) sulfate +copper
a. iron(II) sulfate
b. copper
c. iron
d. Both (a) and (b)
_____ 10. What does CH4 represent in the balanced chemical equation shown below?
C + 2H2 → CH4
a. one atom of CH4
b. five atoms of CH4
c. one molecule of CH4
d. 1 g of CH4
_____ 11. In writing a chemical reaction that produces hydrogen gas, the correct
representation of hydrogen gas is:
a. H
c. 2H
b. H2
d. OH