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Polyatomic Ions > Number Problems > Flashcards

Number Problems Flashcards

1
Q

How many grams of H2O will be formed when 32.0 g H2 is mixed with 12.0 g of O2 and allowed to react to form water?

a. 144 g
b. 6.8 g
c. 286 g
d. 3.4 g
e. 13.5 g

A

e. 13.5 g

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2
Q

A substance contains 35.0 g nitrogen, 5.05 g hydrogen, and 60.0 g oxygen. How many grams of hydrogen are there in a 153-g sample of this substance?

a. 767 g
b. 15.4 g
c. 30.3 g
d. 5.05 g
e. 7.72 g

A

e. 7.72 g

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3
Q

What is the molar mass of ethanol (C2H5OH)?

a. 46.07 g/mol
b. 34.06 g/mol
c. 45.06 g/mol
d. 30.03 g/mol
e. 105.03 g/mol

A

a. 46.07 g/mol

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4
Q

A 7.11-g sample of potassium chlorate was decomposed according to the following equation: 2KClO3->2KCl + 3O2
How many moles of oxygen are formed?

a. 0.0870
b. 0.0580
c. 0.0387
d. 2.78
e. none of these

A

a. 0.0870

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5
Q

When 233.1 g of ethylene (C2H4) burns in oxygen to give carbon dioxide and water, how many grams of CO2 are formed?

a. 8.31 g
b. 182.9 g
c. 365.7 g
d. 299.4 g
e. 731.4 g

A

e. 731.4 g

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6
Q

How many grams of NaCl are contained in 350 mL of a 0.287 M solution of sodium chloride?

a. 16.8 g
b. 5.87 g
c. 11.74 g
d. 100.5 g
e. none of these

A

b. 5.87 g

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7
Q

What mass of solute is contained in 256 mL of a 0.838 M ammonium chloride solution?

a. 11.5 g
b. 175 g
c. 16.3 g
d. 215 g
e. 3.27 g

A

a. 11.5 g

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8
Q

A 1.59-g sample of a metal chloride, MCl2, is dissolved in water and treated with excess aqueous silver nitrate. The silver chloride that formed weighed 3.60 g. Calculate the molar mass of M.

a. 70.9 g/mol
b. 28 g/mol
c. 55.9 g/mol
d. 63 g/mol
e. 72.4 g/mol

A

c. 55.9 g/mol

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9
Q 
Given the following bond energies:
C-C  347 kJ/mol
C=C  614 kJ/mol
C-O  358 kJ/mol
C=O  799 kJ/mol
C-H  413 kJ/mol
O-H  463 kJ/mol
O-O  146 kJ/mol

estimate delta H for the reaction H2O2 + CH3OH -> H2CO + 2H2O.

a. -105 kJ
b. -199 kJ
c. -345 kJ
d. +345 kJ
e. +199 kJ

A

c. -345 kJ

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10
Q

Consider the following processes:

                          delta H (kJ/mol)  3B -> 2C + D      -125 (1/2)A -> B            150 E +A -> D              350

Calculate delta H for: B -> E + 2C

a. -175 kJ/mol
b. 525 kJ/mol
c. 325 kJ/mol
d. -325 kJ/mol
e. none of these

A

a. -175 kJ/mol

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11
Q

Find the enthalpy change, delta H, for the following reaction using the information in the table below.
N2+O2->2NO

a. -301 kJ/mol
b. 829 kJ/mol
c. -222 kJ/mol
d. 222 kJ/mol
e. 301 kJ/mol

A

d. 222 kJ/mol

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12
Q

Find the enthalpy change, delta H°, for the following reaction using the information in the table below.
N2+3H2->2NH3

a. 151 kJ/mol
b. 109 kJ/mol
c. 982 kJ/mol
d. -109 kJ/mol
e. -151 kJ/mol

A

d. -109 kJ/mol

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13
Q

Using the information below, calculate delta H of formation for PbO(s)

PbO(s)+CO(g)->Pb(s) + CO2(g) H°= -131.4 kJ
Hf° for CO2(g) = -393.5 kJ/mol
Hf° for CO(g) = -110.5 kJ/mol

a. +283.0 kJ/mol
b. -151.6 kJ/mol
c. -283.0 kJ/mol
d. -372.6 kJ/mol
e. +252.1 kJ/mol

A

b. -151.6 kJ/mol

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14
Q

At 25°C, the following heats of reaction are known:

                                                   H (kJ/mol) 2ClF + O2 -> Cl2O + F2O            167.4 2ClF3 + 2O2 -> Cl2O + 3F2O     341.4 2F2 + O2 -> 2F2O                        -43.4

At the same temperature, calculate delta H for the reaction: ClF + F2 -> ClF3

a. -108.7 kJ/mol
b. +217.5 kJ/mol
c. -130.2 kJ/mol
d. -217.5 kJ/mol
e. none of these

A

a. -108.7 kJ/mol

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15
Q

The rate constant for a second-order reaction is 0.13 M-1s-1. If the initial concentration of reactant is 0.26 mol/L, it takes _____________s for the concentration to decrease to 0.13 mol/L.

a. 30
b. 1.0
c. 4.4 x 10^-3
d. 0.017
e. 0.50

A

a. 30

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16
Q

In the reaction 2NO2 -> 2NO + O2 at 300°C., [NO2] drops from 0.0100 to 0.00650 M in 100 s. The rate of disappearance of NO2 for this period is ________ M/s.

a. 0.000035
b. 0.0035
c. 0.0018
d. 0.0070
e. 0.35

A

a. 0.000035

17
Q

The reaction

2NO2 -> 2NO + O2

follows second-order kinetics. At 300°C, [NO2] drops from 0.0100 to 0.00650 M in 100 s. Use of the integrated form of the proper rate equation affords a value of _______ L/mol-1s for the rate constant k.

a. 1.2
b. 0.54
c. 0.81
d. 0.096
e. 0.65

A

b. 0.54

18
Q

The initial concentration of reactant in a first order reaction is 0.1 M. The rate constant for the reaction is 0.5 s-1. What is the concentration (in mol/L) of reactant after 1 seconds?

a. 0.165
b. 0.016
c. 0.061
d. 0.05
e. 0.139

A

c. 0.061

19
Q

The half-life of a first-order reaction is 13 min. If the initial concentration of the reactant is 0.085 M, it takes _________ min for it to decrease to 0.055 M.

a. 0.048
b. 3.6
c. 11
d. 8.4
e. 8.2

A

e. 8.2

20
Q

Consider the reaction: 4NH3 + 7O2 -> 4NO2 + 6H2O

At a certain instant the initial rate of disappearance of the oxygen gas is X. What is the value of the appearance of water at the same instant?

a. 1.2 X
b. 0.58 X
c. 0.86 X
d. 1.1 X
e. cannot be determined from the data

A

c. 0.86 X

21
Q

For the reaction: 2SO2(g) -> 2SO(g) + O2(g), the disappearance of SO2(g) was measured to monitor the progress of the reaction.

Calculate the average rate of disappearance of SO2 between 10.0 and 30.0 seconds.

a. 0.0132 M/s
b. 0.00877 M/s
c. 0.00775 M/s
d. 0.00386 M/s
e. 0.00517 M/s

A

c. 0.00775 M/s

22
Q

For a certain process at 355 K, delta G = -11.8 kJ and delta H = -9.2 kJ. Therefore, delta S for the process is

a. 0 J/K mol
b. 7.3 J/K mol
c. -7.3 J/K mol
d. -25.9 J/K mol
e. 25.9 J/K mol

A

b. 7.3 J/K mol

23
Q

Consider the reaction
2N2O5(g) equilibrium 4NO2(g) + O2(g)

at 25°C for which the following data are relevant:

a. -1.35 x 10^5 kJ
b. 98.7 kJ
c. -25.2 kJ
d. 135 kJ
e. 0

A

c. -25.2 kJ

24
Q

The standard free energy of formation of KCl(s) is -408.8 kJ/mol. Delta G° for the reaction 2KCl(s) -> 2K(s) + Cl2(g) is:

a. -408.8 kJ
b. 817.6 kJ
c. 408.8 kJ
d. -817.6 kJ
e. none of these

A

b. 817.6 kJ

25
Q

For the reaction Cl2O(g) + 3/2O2(g) -> 2ClO2(g), delta H° = 126.4 kJ/mol and delta S° = -74.9 J/K mol. At 361°C, what is delta G?

a. 153.4 kJ/mol
b. 47.6 kJ/mol
c. 173.9 kJ/mol
d. 78.9 kJ/mol
e. 155.0 kJ/mol

A

c. 173.9 kJ/mol

Polyatomic Ions (5 decks)

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