Unit Test — Unit test Answers

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The pictures below show samples of different substances.The mass and volume of each sample differ from the mass and volume of the other samples. Is it possible for each sample to contain 1 mol of each substance?

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A
No, because they have different masses.
B
No, because they have different volumes.
C
Yes, if each sample contains 6.02 x 1023 atoms.
D
Yes, if each sample contains 2 amu.
2
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Consider the substances below.• 1 mol of beryllium• 1 mol of salt• 1 mol of water• 1 mol of hydrogenWhich statement is true about these substances?

A
They have exactly the same mass.
B
They have different numbers of particles.
C
They have the same number of atoms.
D
They have different masses.
3

Which statement is true about an empirical formula?

A
It is the true ratio of atoms in a formula unit.
B
It is the simplest ratio of atoms in a formula unit.
C
It represents the true molecular mass of a chemical formula.
D
It represents the highest ratio of coefficients in a chemical formula.
4

The chemical equation below shows the formation of aluminum oxide (Al2O3) from aluminum (Al) and oxygen (O2).4Al + 3O2 2Al2O3The molar mass of O2 is 32.0 g/mol. What mass, in grams, of O2 must react to form 3.80 mol of Al2O3?

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A
60.8 grams
B
81.1 grams
C
122 grams
D
182 grams
5

Nitrogen dioxide, a major air pollutant, can be produced by the combustion of nitrogen oxide as shown. 2NO + O2 2NO2 In a plant, 1,500 kg of nitrogen oxide is consumed per day to produce 1,500 kg of nitrogen dioxide per day. What is the percent yield?Use .

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A
21.7%
B
32.6%
C
43.5%
D
65.2%
6

What is the empirical formula for propene (C3H6)?

A
C2H4
B
C4H8
C
C3H6
D
CH2
7

An unbalanced chemical equation for the reaction of boron fluoride with lithium sulfite is shown below.BF3 + Li2SO3 B2(SO3)3 + LiFWhat is the coefficient of lithium fluoride in the balanced chemical reaction?

Question illustration
A
1
B
3
C
4
D
6
8

The balanced equation shows how sodium chloride reacts with silver nitrate to form sodium nitrate and silver chloride.NaCl + AgNO3 NaNO3 + AgCl If 4.00 g of NaCl react with 10.00 g of AgNO3, what is the excess reactant?

Question illustration
A
AgCl
B
NaCl
C
AgNO3
D
NaNO3
9

In a chemical reaction, substance R reacts with compound XY to produce 47.0 g of compound RX. If the theoretical yield of RX is 56.0 g, what is its percent yield?Use .

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A
9.00%
B
16.1%
C
83.9%
D
119%
10

This formula equation is unbalanced.BaCl2(aq) + Na2CO3(aq) BaCO3(s) + NaCl(aq) Which coefficient should be placed in front of NaCl to balance this equation?

Question illustration
A
1
B
2
C
3
D
4
11

What is the relationship between a mole and Avogadro’s number?

A
A mole is the mass of Avogadro’s number of particles of a substance.
B
A mole is the amount of a compound that has Avogadro’s number of carbon-12 atoms in it.
C
A mole contains Avogadro’s number of particles of a substance.
D
A mole is the amount of any substance that has the same mass as Avogadro’s number of carbon-12 atoms.
12

Which statement best explains the purpose of using a mole in the measurement of matter?

A
It is commonly used as another unit of mass.
B
It allows chemists to deal with a large number of atoms.
C
It is used only for studying the properties of gases.
D
It explains that substances with the same moles have the same mass.
13

Which word equation shows lithium oxide being formed from the reaction between oxygen and lithium?

A
oxygen + lithium oxide lithium
Option A
B
lithium + oxygen lithium oxide
Option B
C
oxygen + lithium lithium + oxide
Option C
D
lithium oxide lithium + oxygen
Option D
14

Sodium combines with water to produce sodium hydroxide and hydrogen gas. Which word equation represents this violent reaction?

A
sodium hydroxide + water sodium + hydrogen
Option A
B
sodium + water sodium hydroxide + hydrogen
Option B
C
sodium + hydrogen sodium hydroxide + water
Option C
D
sodium + sodium hydroxide water + hydrogen
Option D
15

Consider the equation for the formation of water.2H2 + O2 2H2OWhat is the theoretical yield of H2O if 130 g of H2O is produced from 18 g of H2 and an excess of O2?

Question illustration
A
18 g
B
81 g
C
130 g
D
160 g

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