AnswersChemistry - SC3210 A-CRLab: Ionic and Covalent Bonds

Lab: Ionic and Covalent Bonds — Unit test Answers

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1
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Which describes the substances that form covalent bonds?

A
a metal and a metalloid
B
a metal and a nonmetal
C
two nonmetals
D
two metals
2
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The table describes the properties of four compounds.Which compounds are most likely ionic?

Question illustration
A
compounds A and B
B
compounds B and C
C
compounds C and D
D
compounds D and A
3

Which ionic compound is used as a building material?

A
salt
B
limestone
C
magnesium oxide
D
iron oxide
4

Which condition must be met in order for an equation to be balanced?

A
The elements in the reactants are the same as the elements in the products.
B
There are fewer elements in the reactants than there are in the products.
C
The number of atoms in the reactants is greater than the number of atoms in the products.
D
The number of atoms in the reactants equals the number of atoms in the products.
5

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.
6

What best explains whether bromine (Br) or neon (Ne) is more likely to form a covalent bond?

Question illustration
A
Bromine forms covalent bonds because it has seven valence electrons, but neon has eight valence electrons and already fulfills the octet rule.
B
Bromine forms covalent bonds because it has many electron shells, but neon has only two electron shells and is tightly bound to its electrons.
C
Neon forms covalent bonds because it can share its valence electrons, but bromine has seven valence electrons and can gain only one more electron.
D
Neon forms covalent bonds because it has only two electron shells, but bromine has many electron shells and will lose electrons in order to fulfill the octet rule.
7

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.
8

Harvey mixes two liquids. Which observation of the new mixture most likely indicates a precipitate is forming?

A
a cloudy appearance
B
a bubble formation
C
a change in color
D
a change in odor
9

What are the products of the combustion of a hydrocarbon?

A
carbon and oxygen
B
carbon dioxide and water
C
carbon and hydrogen
D
carbon dioxide and hydrogen
10

Which clue can be used to identify a chemical reaction as a decomposition reaction?

A
The reaction involves oxygen.
B
The reaction involves ions.
C
The reaction has a single reactant.
D
The reaction has a single product.
12

Which is a characteristic of all ions?

A
They are metals.
B
They have a charge.
C
They are made of two or more types of atoms.
D
They form chemical bonds through electron sharing.
16

Which balances the equation Mg + O2 → MgO?

A
Mg + 2O2 → 4MgO
B
2Mg + 2O2 → 2MgO
C
2Mg + O2 → 2MgO
D
2Mg + 2O2 → 4MgO
19

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.
20

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

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