AnswersGCSS_Physical Science_ICBalancing Chemical Equations

Balancing Chemical Equations — Unit test Answers

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Hydrochloric acid and sodium hydroxide can be combined to form sodium chloride and water. Which best explains the reaction?

A
The mass of sodium hydroxide will result in the same mass of sodium chloride.
B
The total mass of hydrochloric acid and sodium hydroxide will result in a lower total mass of sodium chloride and water.
C
The mass of hydrochloric acid will result in the same mass of sodium chloride.
D
The total mass of hydrochloric acid and sodium hydroxide will result in the same total mass of sodium chloride and water.
2
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Which best describes a chemical reaction?

A
the rearrangement of atoms by breaking and reforming chemical bonds
B
a reaction that absorbs heat from the surroundings
C
a reaction that releases heat to the surroundings
D
the rearrangement of molecules based on temperature and pressure
3

Chemical A and Chemical B react in an exothermic reaction. What can be known about what will happen when Chemical A and Chemical B are mixed together?

A
The old substance will need more energy to break its chemical bonds than the new substance will release.
B
More energy will be released from the old substance than the new substance will release to form its chemical bonds.
C
The color will change as a result of the reaction.
D
The substance will bubble as a result of the reaction.
4

Which type of reaction has the general formula of AB + CD → AD + CB?

A
synthesis
B
decomposition
C
oxidation
D
replacement
5

Lexi is balancing equations. She is finding one equation to be very difficult to balance. Which explains how to balance the equation ZnSO4 + Li2CO3 → ZnCO3 + Li2SO4?

A
One reactant and one product needs the coefficient 2.
B
The products both need a 3 coefficient.
C
The reactants both need a 2 coefficient.
D
Atoms in the equation are already in balance.
6

When the chemical name of a compound is being written, the subscripts will determine the

A
symbols.
B
elements.
C
prefixes.
D
suffixes.
7

Thirty grams of lead oxide and fifteen grams of ammonia react completely to produce solid lead, nitrogen gas, and liquid water. What will be approximate mass of all three products?

A
10 g
B
15 g
C
45 g
D
450 g
8

"Na2SO3” represents sodium sulfite.What does the 4 mean in the formula 4Na2SO3?

A
There are four atoms of sodium.
B
There are four atoms of sodium sulfite.
C
There are four molecules of sodium sulfite.
D
There are four elements in sodium sulfite.
9

How many chlorine atoms are on the products side of the reaction 2Al + 6HCl → 2AlCl3 + 3H2?

A
2
B
3
C
6
D
9
10

What is used to determine the number of a type of atom in a compound based on the chemical name?

A
the periodic table
B
chemical symbols
C
prefixes
D
the IUPAC
11

Calcium carbonate (CaCO3) is a white solid with no odor. When CaCO3 is heated, the resulting substances are calcium oxide (CaO) and carbon dioxide (CO2). CaO is a white to gray solid with no odor, and CO2 is a gas with no odor and color.Which statement describes CaCO3?

A
It is a diatomic molecule that can’t be broken down by physical means.
B
It is a diatomic molecule that can’t be broken down by chemical means.
C
It is a compound that can be broken down by physical means.
D
It is a compound that can be broken down by chemical means.
12

Sal drew the electron dot diagram of an aluminum atom as shown.

Question illustration
A
He should add five more dots so that the atom obeys the octet rule.
B
He should add ten more dots so that all thirteen electrons are shown.
C
He should add a single dot below the symbol.
D
He should add one dot below and one dot to the left of the symbol.
13

Which refers to the type of chemical bond that involves the transfer of electrons between atoms?

A
metallic
B
polar covalent
C
ionic
D
covalent
14

A __________ at the bottom right side of a chemical symbol represents the number of each type of ion in the chemical formula of an ionic compound.Which best completes the statement?

A
superscript
B
subscript
C
coefficient
D
product
15

Sodium and phosphorus combine to form Na3P. What is the name of this compound?

A
phosphorus sodiate
B
phosphorus sodide
C
sodium phosphate
D
sodium phosphide
16

What else is produced during the replacement reaction of silver nitrate and potassium sulfate?2AgNO3 + K2SO4 Ag2SO4 + ________

Question illustration
A
KNO3
B
2KNO3
C
K2
D
2AgNO3
17

Which refers to the chemical name for NO2?

A
nitrogen dioxygen
B
nitrogen oxide
C
nitrogen dioxide
D
mononitrogen oxygen
18

What does the octet rule state that explains why atoms bond?

A
An atom bonds to have eight valence electrons to become stable.
B
An atom bonds to lose eight valence electrons to become stable.
C
An atom bonds to have eight valence electrons to become unstable.
D
An atom bonds to lose eight valence electrons to become unstable.
19

How many atoms of each element are in the chemical formula Ca(OH)2?

A
1 calcium, 1 oxygen, and 1 hydrogen
B
1 calcium, 2 oxygen, and 2 hydrogen
C
2 calcium, 1 oxygen, and 2 hydrogen
D
2 calcium, 2 oxygen, and 2 hydrogen
20

What prefix should be used for the oxygen atom when naming the chemical formula SO2?

A
mono-
B
pent-
C
di-
D
tri-

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