AnswersIL-Physical Science A-CRUnit Test

Unit Test — Unit test Answers

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Lars is balancing equations with his study group. He is unsure about one equation because each member of the study group came up with a different answer. Which is the proper way to balance the equation Ca(OH)2 + H3PO4 → Ca3(PO4)2 + H2O?

A
Ca(OH)2 + H3PO4 → Ca3(PO4)2 + 6H2O
B
3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O
C
3Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 3H2O
D
Ca(OH)2 + 2H3PO4 → Ca3(PO4)2 + 6H2O
2
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Which is the only element in group 1 on the periodic table that forms covalent bonds?

A
hydrogen
B
lithium
C
potassium
D
sodium
3

Which type of reaction is Mg + S → MgS?

A
polymerization
B
synthesis
C
replacement
D
decomposition
4

Why do natural polymers not pose as much of an issue in landfills as synthetic polymers?

A
Natural polymers are cheap to recycle, and synthetic polymers are expensive to recycle.
B
Natural polymers are expensive to recycle, and synthetic polymers are cheap to recycle.
C
Natural polymers are not biodegradable, and synthetic polymers are biodegradable.
D
Natural polymers are biodegradable, and synthetic polymers are not biodegradable.
5

The equation for water is H2 +O2 → H2O. To balance the equation, which coefficient should be placed in front of H2 and H2O?

A
1
B
2
C
3
D
4
6

Eugene works at a carpet factory. Which natural polymer does he most likely work with to make the carpets?

A
wool
B
rubber
C
nylon
D
silk
7

This chart lists four kinds of polymers and their sources.What can be known about all four polymers, despite their differences?

Question illustration
A
They come from living things.
B
They share ionic carbon bonds.
C
They are at least 100 monomers long.
D
They are made of repeating subunits.
8

Which statement best describes balancing equations and the law of conservation of mass?

A
There are more atoms in the reactants than in the products, and the total mass is the same in the reactants and in the products.
B
The number of atoms is the same in the reactants and in the products, and the total mass is the same in the reactants and in the products.
C
There are fewer atoms in the reactants than in the products, and the total mass is less in the reactants than in the products.
D
There are more atoms in the reactants than in the products, and the total mass is higher in the reactants than in the products.
9

Ciara’s bike has rusted, which means that the iron in the metal changed to rust.

A
an energy formation
B
an exothermic reaction
C
a chemical reaction
D
a precipitate formation
10

What is a limitation of using a chemical formula, such as C6H12O6, to represent a compound?

A
The chemical formula does not show the types of elements that make up the compound.
B
The chemical formula does not show how the atoms are connected to one another.
C
The chemical formula does not show the number of atoms of each element in a molecule.
D
The chemical formula does not show the chemical symbols of the elements in the compound.
11

Which statement best describes the difference between endothermic and exothermic reactions?

A
They are opposites because endothermic reactions require energy and exothermic reactions release energy.
B
They are opposites because endothermic reactions release energy and exothermic reactions require energy.
C
They the same because they are both ways of forming precipitates.
D
They the same because they are both ways of forming gasses.
12

How do the nuclei of covalently bonded atoms help keep the bond together?

A
Neutral particles in the nucleus provide enough mass that the force of gravity holds the atoms together.
B
Neutral particles in the nucleus can become positive or negative in order to balance the charges.
C
Positive particles in the nucleus change into negative particles that enter electron shells.
D
Positive particles in the nucleus are attracted to shared electrons, so the atoms stay close together.
13

Which term best describes all atoms in ionic bonds?

A
stable
B
unstable
C
positively charged
D
negatively charged
14

When balanced, which equation would have the coefficient 3 in front of any of the reactants?

A
Zn + HCl ZnCl2 + H2
Option A
B
H2SO4 + B(OH)3 B2(SO4)3 + H2O
Option B
C
Fe + AgNO3 Fe(NO3)2 + Ag
Option C
D
C2H4O2 + O2 CO2 +H2O
Option D
15

Lionel has a hot plate, a thermometer, a container of water, a spoon, and a small hammer. Using these tools, Lionel can test several properties of an ionic compound.Which property of the compound will he not be able to test?

A
atomic structure
B
melting point
C
ability to dissolve
D
brittleness

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