Chem – 131 – section 001 – spring 2016 – general chemistry lec ii

 

 

10165 – CHEM – 131 – Section 001 – Spring 2016 – General Chemistry Lec II

 

 

Question 1

Correct

Mark 3.00 out of 3.00

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All of the following are clues that a chemical reaction has taken place except

The reactant is smaller.

a.A flame occurs.

b.A color change occurs.

c. A solid forms.

 

Question 2

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Balance the following equation in standard form and determine the sum of the coefficients.

a.6

b.4

c.3

d.14

e.7

Question 3

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Balance this equation using the smallest possible integers, S + HNO₃ → H₂SO₄ + NO₂ + H₂O. What is the coefficient of water.

Select one:

a.2

b.6

c.8

d. 1

e.

Question 4

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When the following equation is balanced using the smallest possible integers, what is the coefficent of oxygen gas?

C₇H₁₆(g) + O₂(g) → CO₂(g) + H₂O(g)

a.5   

b.11

c.2

d.14

e.8

Question 5

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True or false? The equation N₂ + 3H₂ → 2NH₃ means that 1 g of N₂ reacts with 3 g of H₂ to form 2 g of NH₃.

Question 6

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Which of the following statements is not true of balancing a chemical equation?

Select one:

a.Subscripts in the reactants must be conserved in the products.

b.The law of conservation of matter must be followed.

c.Phases are often shown for each compound but are not critical to balancing an equation.

d.All of the above statements (a-d) are true.

e.Coefficients are used to balance the atoms on both sides.

Question 7

CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g)

Select one:

a.oxidation-reduction

b.two of these

c.synthesis

d. decomposition

e.combustion

Question 8

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Classify the following reaction:

2Mg(s) + O₂(g) → 2MgO(s)

Select one:

a.synthesis

b.oxidation-reduction

c. a-c are all correct.

d.combustion

e.two of the above

Question 9

The equation 2Ag₂O(s) → 4Ag(s) + O₂(g) is a(n) ______________ reaction.

Select one:

a.synthesis

b.two of these

c. oxidation-reduction

d.decomposition

e.combustion

Question 10

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The reaction 2K(s) + Br₂(l) → 2KBr(s) is a(n) ______________ reaction.

Select one:

a.acid-base

b.oxidation-reduction

c.precipitation

d. single-replacement

e.double-displacement

Question 11

When the following equation is balanced in standard form, what is the coefficient in front of the H₂O?
C₈H₁₈(g) + O₂(g) CO₂(g) + H₂O(g)

a.8

b.18

c.16

d.25

e.1

Question 12

Which of the following is a strong acid?

Select one:

a.phosphoric acid

b.acetic acid

c.hydrofluoric acid

d.lactic acid

e.hydrochloric acid

Question 13

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Which of the following statements is not true?

a.Two nonmetals can undergo an oxidation-reduction reaction.

b.A metal-nonmetal reaction involves electron transfer.

c.When two nonmetals react, the compound formed is ionic.

d.A metal-nonmetal reaction can always be assumed to be an oxidation-reduction reaction.

e.When a metal reacts with a nonmetal, an ionic compound is formed.

Question 14

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17.7 g of Mg represents how many moles?

Select one:

a.none of these

b.1.37 mol

c.42.0 mol

d.4.30 × 10² mol

e.0.728 mol

Correct

Question 15

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21.2 g of oxygen contains

a.none of the above

b.1.28 × 10²⁵ oxygen molecules

c.7.98 × 10²³ oxygen atoms

d.42 amu

e.1.33 mol of oxygen molecules

Question 16

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45 atoms of calcium weigh

Select one:

a.1.804 × 10³ g

b.900 amu

c.900 g

d.1.804 × 10³ amu

e.2.71 × 10²⁵ amu

Question 17

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8.55 x 10^-3 moles of an unknown compound has a mass of 0.257 g. The compound could be:

Select one:

a.C₅H₁₂

b.CH₄

c.C₃H₈

d.C₂H₆

e.C₄H₁₀

Question 18

A 1.73-mole sample of H₂O₂ weighs

Select one:

a. 31.2 amu

b. 31.2 g

c. 1.73 g

d. 58.8 g

e 35.7 g

Question 19

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A certain compound has an empirical formula of NH₂O. Its molar mass is between 55 and 65 g/mol. Its molecular formula is

Select one:

a N₂H₄O₂

b N₂H₂O₂

c NH₂O

d not calculable

Question 20

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A certain compound is found to have the percent composition (by mass) of 85.63% C and 14.37% H. The molecular formula contains 3 carbon atoms. How many hydrogen atoms are contained in a molecular of this compound?

Select one:

A 8

b3

c 2

d 4

 e 6

Question 21

A compound is composed of element X and hydrogen. Analysis shows the compound to be 80% X by mass, with three times as many hydrogen atoms as X atoms per molecule. Which element is element X?

Select one:

A F

b none of these

c He

d S

e C

22

Calculate the mass of 5.333 moles of silver nitrate.

a.none of these

b.906.1 g

c.820.8 g

d.31.9 g

e.3.139 × 10^–2 g

Question 23

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Convert: 3.577 mol K₂O = _____________ g K₂O

a.26.33

b 3.577

 c.337.0

d 3.797 × 10^–2

e 2.154 × 10²⁴

Question 24

Convert: 9.41 mol Cu(NO₃)₂ = ____________ g Cu(NO₃)₂

Select one:

none of these

b 1.77 × 10³

c 1.61 × 10³

d 5.02 × 10^–2

e 19.9

Question 25

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Determine the percentage composition (by mass) of tin in SnCl₂.

Select one:

a.62.6 %

b.77.0 %

c 38.5 %

d 61.5 %

e 18.7 %

Question 26

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The empirical formula of styrene is CH; its molar mass is 104.1 g/mol. What is the molecular formula of styrene?

Select one:

a.C₈H₈

b.C₂H₄

c C₆H₆

d C₁₀H₁₂

Question 27

What is the molar mass of Li₃PO₄?

Select one:

a 83.79 g/mol

b 115.79 g/mol

c 108.85 g/mol

d 6.02 × 10²³ g/mol

e 84.82 g/mol

Question 28

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Which represents the greatest mass?

Select one:

a.1.0 mol P

b.1.0 mol K

c. all the same

d.1.0 mol Al

e.1.0 mol I

Question 29

True or false? One atomic mass unit (amu) is the mass (in grams) of one mole of the substance.

Question 30

True or false? The empirical formula and the molecular formula for a compound cannot be the same.

Question 31

True or false? The mole can be defined as the number equal to the number of oxygen atoms in 32.00 g of oxygen.

Question 32

An excess of Al and 9.7 mol of Br₂ are reacted according to the equation

 

How many moles of AlBr₃ will be formed assuming 100% yield?

Select one:

a.4.9 mol

b.6.5 mol

c.9.7 mol

d.14.6 mol

e.3.2 mol

Question 33

Calculate the mass of water produced when 6.25 g of methane, CH₄, reacts with an excess of oxygen in the following unbalanced reaction.

 

Select one:

a.       7.02 g H₂O

b 0.78 g H₂O

c.       14.0 g H₂O

d.2.25 × 10² g H₂O

e.0.347 g H₂O

Question 34

Consider the equation: . The molar mass of B is 50.0 g/mol. Which of the following statements is true when equal masses of A and B are reacted?

a.If the molar mass of A is less than the molar mass of B, then B must determine how much C is produced.

b. If the molar mass of A is greater than the molar mass of B, then B must determine how much C is produced.

c.If the molar mass of A is greater than the molar mass of B, then A must determine how much C is produced.

d.If the molar mass of A is less than the molar mass of B, then A must determine how much C is produced.

e If the molar mass of A is the same as the molar mass of B, then A and B react in a perfect stoichiometric ratio and both determine how much C is produced.

Question 35

Consider the following unbalanced equation:
How many moles of water are needed to react with 232. g of Al₄C₃?

a.0.620 mol

b.0.134 mol

c 19.3 mol

d 1.61 mol

e 348. mol

Question 36

Tin(II) fluoride is added to some dental products to help prevent cavities. Manufacturers have to make the tin(II) fluoride first, though, before they can add it to their products.

 

How many grams of tin(II) fluoride can be made from 58.0 g of hydrogen fluoride if there is plenty of tin available to react?

a.       908. g

B 227. g

c 116. g

d 454. g

e 1.45 g

Question 37

What mass of carbon dioxide will be produced when 12.9 g of butane reacts with an excess of oxygen in the following reaction?

 

a none of these

 b 39.1 g CO₂

c 4.88 g CO₂

d 78.1 g CO₂

e 51.6 g CO₂

Question 38

True or false? A balanced chemical equation is one that has the same number of moles of molecules on each side of the equation.

Question 39

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True or false? A mole ratio is used to convert the moles of a starting substance to the moles of a desired substance.

Question 40

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True or false? The equation can be interpreted by saying that 1 mol of N₂ reacts with 3 mol of H₂ to form 2 mol of NH₃.

Question 41

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A hydrogen balloon is at 25^oC, 1.00 atm and has a volume of 1.00 L. How many grams of argon gas must be added to the hydrogen balloon to achieve a volume of 3.84 L at constant temperature and pressure?

Select one:

a 4.64 g

b 93.9 g

c none of these

d 6.27 g

e 7.91 g

Question 42

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A sample of an ideal gas containing 0.918 mol is collected at 742 torr pressure and 31°C. Calculate the volume.

Select one:

aL

b 23.5 L

cL

d none of these

e 2.39 L

Question 43

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A sample of oxygen gas (O₂) has a volume of 7.86 L at a temperature of 19^oC and a pressure of 1.38 atm. Calculate the moles of O₂ molecules present in this gas sample.

Select one:

A none of these

B 0.226 mol

 

C 6.96 mol

D 0.905 mol

E 0.453 mol

Question 44

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An oxygen sample has a volume of 9.77 L at 27°C and 800.0 torr. How many oxygen molecules does it contain?

 

Question 45

Avogadro’s law states that:

a The volume of a fixed amount of gas is indirectly proportional to its temperature in Kelvin at constant pressure.

b The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature.

c The total pressure of a mixture of gases is the simple sum of the partial pressure of all of the gaseous compounds.

d Equal amounts of gases occupy the same volume at constant temperature and pressure.

e The volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure.

Question 46

Boyle’s law states that:

Select one:

a Equal amounts of gases occupy the same volume at constant temperature and pressure.

b The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature.

c The volume of a fixed amount of gas is proportional to its pressure at constant temperature.

d The volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure.

e The total pressure of a mixture of gases is the simple sum of the partial pressure of all of the gaseous compounds.

Question 47

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Charles’s law states that:

a.The volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature.

b. The total pressure of a mixture of gases is the simple sum of the partial pressure of all of the gaseous compounds.

C The volume of a fixed amount of gas is directly proportional to its temperature in Kelvin at constant pressure.

D The volume of a fixed amount of gas is indirectly proportional to its temperature in Kelvin at constant pressure.

E Equal amounts of gases occupy the same volume at constant temperature and pressure.

Question 48

A solution has [H⁺] = 4.7 × 10^-8 M. The pH of this solution is

a.9.80

b.7.33

c.6.01

d. none of these

e.6.67

Question 49

A solution has a pH of 3.66. The pOH of this solution is

Select one:

a.10.34

b.none of these

c.10.24

d.3.76

e. 3.66

Question 50

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A solution where [H⁺] = 10^-13 M is ______________.

Select one:

A acidic

B basic

C strongly acidic

d.neutral

e.two of these

Question 51

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Calculate the [H⁺] in a solution that has a pH of 2.39.

Select one:

aM

b none of these

c 11.61 M

d 2.39 M

eM

Question 52

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What is the pH of a 3.6 M solution of HClO₄?

Select one:

[removed]a.

0.56

[removed]b.

13.44

[removed]c.

–0.56

[removed]d.

14.56

[removed]e.

minus infinity

Question 53

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What is the pH of a solution that has [OH^–] = .

Select one:

[removed]a.

3.84 M

[removed]b.

1.92 M

[removed]c.

none of these

[removed]d.

10.16 M

[removed]e.

6.90 M

Question 54

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Which of the following is not a strong acid?

Select one:

[removed]a.

HClO₄

[removed]b.

H₂SO₄

[removed]c.

CH₃COOH

[removed]d.

HCl

[removed]e.

HNO₃

Question 55

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Which of the following statements is/are correct?

Select one:

[removed]a.

None of the above statements (a-c) are correct.

[removed]b.

In a basic solution, [OH^–] > [H⁺].

[removed]c.

All of the above statements (a-c) are correct.

[removed]d.

In an acidic solution, [H⁺] > [OH^–].

[removed]e.

In a neutral solution, [H⁺] = [OH^–].

Question 56

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Choose the correct Lewis structure for the NH₄⁺ ion.

Select one:

[removed]a.

 

[removed]b.

 

[removed]c.

none of these

[removed]d.

 

[removed]e.

 

Question 57

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Consider the drawings below:

 

Which of the following statements are true?

I. The electrons in each molecule tend to be attracted to the most electronegative element.
II. Each molecular drawing follows the localized electron model.
III. Both HF and CO₂ are linear molecules and therefore nonpolar.
IV. The bond angles of NH₃ are slightly less than 109.5^o because the lone pair compresses the angles between the bonding pairs.

Select one:

[removed]a.

II, IV

[removed]b.

All of the above statements (I – IV) are correct.

[removed]c.

I, III, IV

[removed]d.

I, II, III

[removed]e.

I, II, IV

Question 58

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How many lone pairs of electrons are in the Lewis structure for compound, HF?

Select one:

[removed]a.

3

[removed]b.

4

[removed]c.

1

[removed]d.

0

[removed]e.

none of these

Question 59

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How many of the following will have Lewis structures with multiple bonds?
CO, CO₂, CO₃^2-, N₂, O₂

Select one:

[removed]a.

2

[removed]b.

1

[removed]c.

3

[removed]d.

5

[removed]e.

4

Question 60

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The number of polar covalent bonds in SF₄ is

Select one:

[removed]a.

none of these

[removed]b.

3

[removed]c.

2

[removed]d.

4

[removed]e.

1

Question 61

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Which has a bent structure?

Select one:

[removed]a.

NH₃

[removed]b.

CO₂

[removed]c.

CaCl₂

[removed]d.

O₂

[removed]e.

H₂O

Question 62

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Which has a linear structure?

Select one:

[removed]a.

SCl₂

[removed]b.

OF₂

[removed]c.

CO₂

[removed]d.

CaCl₂

[removed]e.

SO₂

Question 63

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Which has a planar structure?

Select one:

[removed]a.

CO₃^2-

[removed]b.

H₃O⁺

[removed]c.

CH₄

[removed]d.

NF₃

[removed]e.

SO₃^2-

Question 64

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Which has a tetrahedral structure?

Select one:

[removed]a.

CO₃^2-

[removed]b.

NH₃

[removed]c.

SO₃

[removed]d.

CH₄

[removed]e.

SO₃^2-

Question 65

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Which has a trigonal pyramid structure?

Select one:

[removed]a.

NO₃^–

[removed]b.

SO₃^2-

[removed]c.

CO₃^2-

[removed]d.

CH₄

[removed]e.

SO₃

Question 66

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Which of the following bonds does not have a dipole moment?

Select one:

[removed]a.

C-H

[removed]b.

B-F

[removed]c.

Br-H

[removed]d.

F-F

[removed]e.

F-H

Question 67

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Which of these has more than one reasonable resonance structure?

Select one:

[removed]a.

SiCl₄

[removed]b.

BH₄^–

[removed]c.

NO₃^–

[removed]d.

N₂H₄

[removed]e.

PH₃

Question 68

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True or false? A bond is a force that holds groups of two or more atoms together and makes them function as a unit.

Select one:

[removed]True

[removed]False

Question 69

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True or false? CH₄ has ionic bonds.

Select one:

[removed]True

[removed]False

Question 70

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True or false? Covalent bonding occurs when a metal reacts with a nonmetal.

Select one:

[removed]True

[removed]False