AnswersLAUSD-Chemistry in the Earth System BCumulative Exam

Cumulative Exam — Cumulative exam Answers

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The chemical equation below shows the burning of magnesium (Mg) with oxygen (O2) to form magnesium oxide (MgO).2Mg + O2 2MgOThe molar mass of O2 is 32.0 g/mol. What mass, in grams, of O2 is required to react completely with 4.00 mol of Mg?

Question illustration
A
2.00 grams
B
64.0 grams
C
128 grams
D
256 grams
2
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Which is one factor that contributes to the formation of polar, temperate, and tropical zones?

A
the angle of the Sun’s rays
B
the direction of seasonal winds
C
the presence of prevailing winds
D
the movement of wind near a mountain
3

Which task most likely involves a calculation that uses moles?

A
measuring a sugar sample on a balance
B
counting the number of jellybeans in a jar
C
determining the number of atoms in a jar of liquid
D
finding the rate of expansion of a gas-filled balloon
4

The pOH of a solution is 6.0. Which statement is correct?Use and .

Question illustration
A
The pH of the solution is 20.0.
B
The concentration of OH– ions is .
Option B
C
The concentration of OH– ions is .
Option C
D
The pH of the solution is 8.0.
5

The cryosphere is part of which sphere of the Earth system?

A
atmosphere
B
biosphere
C
geosphere
D
hydrosphere
6

Which is the formula mass of Na2SO4?

A
119.06 amu
B
125.98 amu
C
142.05 amu
D
174.12 amu
7

Ca(OH)2 is added to a large beaker of water. How is the solution different from the original water?

A
The solution turns blue litmus to red.
B
The solution turns phenolphthalein pink.
C
The solution has more hydrogen ions.
D
The solution has fewer hydroxide ions.
8

The chemical equation below shows the combustion of methane (CH4).CH4 + 2O2 CO2 + 2H2OThe molar mass of oxygen gas (O2) is 32.00 g/mol. The molar mass of carbon dioxide (CO2) is 44.01 g/mol. What mass of CO2, in grams, will form when 8.94 g O2 completely react?

Question illustration
A
3.25 grams
B
6.15 grams
C
13.0 grams
D
53.0 grams
9

When does the Northern Hemisphere receive the fewest hours of daylight?

A
during the fall equinox
B
during the winter solstice
C
during the spring equinox
D
during the summer solstice
10

What is the importance of having the US Forest Service, the Bureau of Land Management, the US Fish and Wildlife Service, and the National Park Service?

A
to manage land resources for conservation and the development of natural resources
B
to manage land resources for conservation and the development of urban areas
C
to preserve historical landmarks and manage the development of urban areas
D
to preserve historical landmarks and manage the development of rural areas
11

How can the process of climate change best be described?

A
artificial and sporadic
B
dangerous and quick
C
natural and continuous
D
unnatural and short-term
12

Consider the half reactions below for a chemical reaction.What is the overall equation for this chemical reaction?

Question illustration
A
Upper M g (s) plus 2 upper H superscript plus (a q) right arrow upper M g superscript 2 plus (a q) plus upper H subscript 2 (g).
Option A
B
Upper M g (s) plus 2 upper H superscript plus (a q) right arrow upper M g superscript 2 plus (a q) plus 2 e superscript minus.
Option B
C
Upper M g superscript 2 plus (a q) plus upper H subscript 2 (g) right arrow upper M g (s) plus 2 upper H superscript plus (a q).
Option C
D
Upper M g (s) plus 2 upper H right arrow upper M g (a q) plus upper H subscript 2 (g).
Option D
13

In which era did mammals emerge?

A
Cenozoic
B
Mesozoic
C
Paleozoic
D
Precambrian
14

The molar mass of NaOH is 40.00 g/mol. If 5.20 g NaOH are dissolved in 0.500 L of solution, what is the molarity of the solution?Use .

Question illustration
A
0.0125 M
B
0.260 M
C
3.85 M
D
7.69 M
15

Which option identifies ways that people positively affect Earth’s resources?

A
use cars that emit fewer harmful gases, build dams, and stop using all resources
B
stop using all resources, increase mining efforts, and halt the runoff of factory waste into rivers and streams
C
build dams, use cars that emit fewer harmful gases, and halt the runoff of factory waste into rivers and streams
D
increase mining efforts, build dams, and use cars that emit fewer harmful gases
16

What is one way people have negatively affected land resources?

A
habitat restoration
B
urbanization
C
terrace farming
D
reforestation
17

Which of the following is an oxidation-reduction reaction?

A
SO2(g) + H2O(l) H2SO3(aq)
Option A
B
CaCO3(s) CaO(s) + CO2(g)
Option B
C
Ca(OH)2(s) + H2CO3(l) CaCO3(aq) + 2H2O(l)
Option C
D
C6H12O6(s) + 6O2(g) 6CO2(g) + 6H2O(l)
Option D
18

Consider the reaction below.2C6H14 + 19O2 12CO2 + 14H2OHow many moles of hexane (C6H14) must burn to form 18.4 mol of carbon dioxide?

Question illustration
A
1.53 mol
B
3.07 mol
C
110. mol
D
175. mol
19

Which is the first step in the dissolving process?

A
The solute becomes like the solvent.
B
The solute molecules are carried into the solution.
C
The solvent molecules surround the solute particles.
D
The solvent molecules are attracted to particles at the surface of the solute.
20

In an experiment, a student wants to increase the rate of a reaction that involves gases. Which change to the reactants would accomplish this?

A
Increase the volume to decrease pressure and to increase concentration.
B
Increase the volume to increase pressure and to decrease concentration.
C
Decrease the volume to decrease pressure and to increase concentration.
D
Decrease the volume to increase pressure and to increase concentration.

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