Physical Science, New York Edition

Chapter 21: Chemical Reactions

Section 2 Self-Check Quiz-Eng.

1.
In chemical equations, __________ represent the number of units of each substance.
A)coefficients
B)reactants
C)products
D)precipitates
2.
Which reactant correctly balances the following equation: 4Al + __________ → 2Al2O3?
A)3O2
B)O3
C)3O
D)2O2
3.
What is the correct coefficient for mercury(II) oxide (HgO) in the following equation: HgO → 2Hg + O2?
A)1
B)4
C)2
D)3
4.
Some elements usually exist in combinations of two atoms. These combinations are called __________ .
A)diatomic molecules
B)isotopes
C)ions
D)coefficients
5.
The chemical formula for a compound tells __________ .
A)how stable the compound is
B)what type of chemical bond it forms
C)what elements it contains
D)how electrons are arranged
6.
Why is oxygen written with a subscript 2?
A)Its mass is twice as great as the reactants'.
B)There are two times as many oxygen atoms as reactant atoms.
C)It usually exists as a diatomic molecule.
D)Its mass increases by two times as a result of the reaction.
7.
What does it mean for a chemical equation to be balanced?
A)The solid products weigh the same as the reactants.
B)The same number of atoms of each element is on both sides of the equation.
C)The reactants and the products are written with the same coefficients.
D)The number of reactants is equal to the number of products.
Physical Science - New York Edition
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