Molar Relationships

Molar Relationships

The pH of a 0.1 molar aqueous solution of HCl would equal —

A -1

B 1

C 11

D 13

If 3.50 g of H2S are used in the

above reaction, what will be the theoretical yield of water in grams?

A 0.102 g

B 0.185 g

C 1.85 g

D 185 g



OmolH

OgHx

SmolH

OmolHx

SgH

SmolHx

SgH

2

2

2

2

2

22

1

18

2

2

1.34

15.3



A 0.102 g

B 0.185 g

C 1.85 g

D 185g

Which of the following aqueous solutions will cause litmus paper to turn red?

A NaOH

B NaCl

C HCl

D H2O

Which of the following substances is a weak electrolyte?

A 0.66 M

B 0.97 M

C 1.03 M

D 1.52 M

A solution contains 225 g of glucose, C6H12O6, dissolved in

enough water to make 0.825 L of solution. What is the molarity of the solution?



6126

61266126

180

1

825.0

225

OHgC

OHmolCx

L

OHgC

L

molM

A 0.66 M

B 0.97 M

C 1.03 M

D 1.52 M



Carbon disulfide is prepared industrially by reacting carbon with sulfur dioxide according to the above equation. If 5.9 moles of carbon react, how many moles of CS2 are produced?

A 0.077 moles B 1.2 moles

C 1.5 moles D 30 moles


molC

molCSx

molC

5

19.5 2


A 0.077 moles B 1.2 moles

C 1.5 moles D 30 moles

A solution which has a concentration that exceeds its predicted solubility at a certain temperature and pressure would be —

A unsaturated

B saturated

C supersaturated

D dilute

How many milliliters of 2.00 M H2SO4 are needed to provide 0.250

mole of H2SO4?

A 125 mL

B 1.25 x 101 mL

C 8.00 x 103 mL

D 8.00 mL


mole of H2SO4?

L

mLx

SOmolH

Lx

SOmolH

1

1000

2

1250.

42

42


mole of H2SO4?

A 125 mL

B 1.25 x 101 mL

C 8.00 x 103 mL

D 8.00 mL

What is the molarity of a solution prepared by dissolving 27.2 g of sodium chloride in enough water to prepare 500.0 mL of solution?

A 0.186 MB 0.465 MC 0.930 M D 1.860 M

http://www.pelletlab.com/images/2306.jpg


l

mLx

gNaCl

molNaClx

mL

gNaCl

L

molM

1

1000

5.58

1

0.500

2.27


A 0.186 MB 0.465 MC 0.930 M D 1.860 M

http://www.pelletlab.com/images/2306.jpg

When copper reacts with silver nitrate according to the equation, the number of grams of copper required to produce 432 grams of silver is —

A 31.5 gB 127 g C 216 gD 252 g


molCu

gCux

molAg

molCux

gAg

molAgx

gAg

1

5.63

2

1

9.107

1432


A 31.5 gB 127 g C 216 gD 252 g

What is the final concentration if 50.0 mL of a 2.00 M solution are diluted to 500.0 mL?

A 0.100 MB 0.200 M C 0.400 MD 1.00 M


2211 VMVM


mL

mLMx

V

VMM

0.500

0.5000.2

2

112


A 0.100 MB 0.200 M C 0.400 MD 1.00 M

The number of grams of oxygen required for the complete combustion of 4.00 grams of methane (CH4) is —

A 4.00 g

B 8.00 g

C 16.0 g

D 32.0 g

http://www.ozoneservices.com/products/OLO/images/tank/01-b.jpg


2

2

4

2

4

44

1

32

1

2

16

100.4

molO

gOx

molCH

molOx

gCH

molCHx

gCH


A 4.00 g

B 8.00 g

C 16.0 g

D 32.0 g

http://www.ozoneservices.com/products/OLO/images/tank/01-b.jpg

Zn + 2HCl → ZnCl2 + H2

If 0.600 gram of zinc is used, what is the amount of zinc chloride that is produced in the above reaction?

A 0.125 gramB 1.25 grams C 12.5 gramsD 0.018 gram



2

22

1

4.136

1

1

4.65

1600.0

molZnCl

gZnClx

molZn

molZnClx

gZn

molZnx

gZn



A 0.125 gramB 1.25 grams C 12.5 gramsD 0.018 gram

Four aqueous solutions and their concentrations are shown in the above illustration. Which of the solutions is most likely to be the strongest conductor of electricity?

A. I B. II C. III D. IV

)()()(2

aqaqOH

s ClNaNaCl

)(6126)(61262

aqOH

s OHCOHC

I 2 x .5 or 1M

II 2 x 1.5 or 3M

III 1 x .5 or .5M

IV 1 x 1.5 or 1.5 M

Four aqueous solutions and their concentrations are shown in the above illustration. Which of the solutions is most likely to be the strongest conductor of electricity?

A. I B. II C. III D. IV

In the reaction 2SO2 (g) + O2 (g) 2SO3 (g), which change would cause the greatest increase in the concentration of SO3?

A Decrease the concentration of SO2

B Decrease the concentration of O2

C Increase the concentration of SO2

D Increase the concentration of O2

2H2(g) + 02(g) 2H2O(g) How many liters of oxygen are required

to produce 2 liters of water at STP?

A 1 B 2C 3D 4



2

2

2

2

2

22

1

4.22

2

1

4.22

12

molO

LOx

OmolH

molOx

OLH

OmolHx

OLH



A 1 B 2C 3D 4

The molar volume of an ideal gas in liters at STP is — A 6.02 x 1023 LB 11.2 LC 22.4 L D 0.0821 L

What is the density of carbon dioxide at STP?

A 1.96 g/L B 22.0 g/C 46.0 g/LD 5.09 x 10-1 g/L V

mD

What is the density of carbon dioxide at STP? Carbon Dioxide is CO2

L

g

V

mD

4.22

0.44

Mass CO2 = 1(12.0) + 2(16.0) = 44.0g

Volume at STP is 22.4L

What is the density of carbon dioxide at STP?

A 1.96 g/L B 22.0 g/C 46.0 g/LD 5.09 x 10-1 g/L

Which of these is about 2 moles?

A 2.0 liters (dm3) of H2

B 4.0 grams of H2

C 2.0 x 1023 molecules of H2

D 4.0 kilograms of H2


2 mol of a gas (STP) = 2(22.4 L)

2 mol = 2(6.02 x 1023)

2 mol = 2(2.0g)


A 2.0 liters (dm3) of H2

B 4.0 grams of H2

C 2.0 x 1023 molecules of H2

D 4.0 kilograms of H2

When magnesium metal (Mg) is burned, it forms MgO. How many moles of oxygen gas (O2) are needed to burn 10 moles of Mg?

A 2B 5 C 10D 20

http://www.angelo.edu/faculty/kboudrea/demos/burning_magnesium/BurningMg05.jpg


MgOOMg 22 2

molMg

molOx

molMg

2

110 2


A 2B 5 C 10D 20

http://www.angelo.edu/faculty/kboudrea/demos/burning_magnesium/BurningMg05.jpg

Nitrogen gas is a diatomic molecule. What is the mass of one mole of nitrogen gas?

A 7 gB 14 gC 28 g D 6 x 1023 g


Molar mass from Periodic Table

N2 2(14.0 g) =


A 7 gB 14 gC 28 g D 6 x 1023 g

Which volume will be occupied by a gas containing 6.02 x 1023 atoms at STP?

A 1.0 LB 11.2 LC 22.4 L D 44.8 L


6.02 x 1023 = 1 mol

1 mol gas = 22.4 L


A 1.0 LB 11.2 LC 22.4 L D 44.8 L

Ulcers are often caused by an excess of stomach acid. Milk of magnesia is often used to soothe the irritation. Milk of magnesia is probably —

A an acidB a base C an indicatorD a colloid

The hydrogen ion concentration is 1 x 10-7. What is the pH of this solution? A 1B 7 C 10D 14

How many grams of sodium chloride are required to prepare 500.0 mL of a 0.100 M solution?

A. 1.46 g

B. 2.93 g

C. 29.3 g

D. 58.5 g

How many grams of sodium chloride are required to prepare 500.0 mL of a 0.100 M solution?

mol

gNaClx

l

molNaClx

ml

LmLx

1

5.58

1

100.0

1000

10.500

A. 1.46 g

B. 2.93 g

C. 29.3 g

D. 58.5 g

What mass of potassium hydroxide is required to react completely with 2.70 g of sulfuric acid to produce potassium sulfate

and water?

A. 4.73 gB. 3.09 g C. 2.36 gD. 1.54 g

2KOH + H2SO4 → 2H2O + K2SO4

What mass of potassium hydroxide is required to react completely with 2.70 g of sulfuric acid to produce potassium sulfate

and water?

2KOH + H2SO4 → 2H2O + K2SO4

molKOH

gKOHx

SOmolH

molKOHx

SOgH

SOmolHxSOgH

1

1.56

1

2

1.98

170.2

4242

4242

A. 4.73 gB. 3.09 g C. 2.36 gD. 1.54 g

How many grams of product Z will be formed if 12.0 g of W react with 10.0 g of X to form 8.0 g of product Y in the reaction

shown?

A. 8.0 g

B. 10.0 g

C. 12.0 g

D. 14.0 g

W + X → Y + Z

Remember Conservation of Mass

12 + 10 = Z + 8

22-8 = z

If 6 liters of hydrogen gas are used,how many liters of nitrogen gas will beneeded for the above reaction at STP?

A. 2 liters

B. 3 liters

C. 4 liters

D. 12 liters

N2 + 3H2 → 2NH3

2

2

2

2

2

22 1

4.22

3

1

4.22

16

molN

LNx

molH

molNx

LH

molHxLH

The gas with the largest volume at STP is —

A. 10.0 g He

B. 10.0 g Ne

C. 10.0 g Ar

D. 10.0 g Kr


molHegHe

molHegHex 50.2

4

10.10

molNegNe

molNegNex 500.0

2.20

10.10

molArgAre

molArgArx 251.0

9.39

10.10

molKrgKre

molKrgKrx 122.0

8.83

10.10


A. 10.0 g He

B. 10.0 g Ne

C. 10.0 g Ar

D. 10.0 g Kr

A has the greatest amount of moles therefore it has the largest volume

Which pair of solutions would be acidic if mixed in equal quantities? Solution A B C D

pH 2 6 9 12

A. A and B B. B and CC. B and DD. C and D

2 + 6 = 8/2 = 46 + 9 = 15/2 = 7.56 + 12 = 18/2 = 99 + 12 =21/2 =10.5

What is represented by the pH of a solution?

A. Partial pressure of hydrogen ions in the solution

B. Electronegativity of dissociated hydrogen ions in the solution

C. Concentration of hydrogen ions in the solution

D. Temperature of hydrogen ions in the solution

A container holds 20.0 grams of neon gas. Under the same conditions, how many

grams of xenon would the container hold?

A. 108 g

B. 131 g

C. 262 g

D. 370 g

20.0 g Ne is about 1 mole therefore they container would also hold 1 mole of Xeon under the same conditions therefore the mass of Xeon in the container would be about ……

How many grams of nitrogen are present in 2 moles of HNO3?

A. 1

B. 2

C. 14

D. 28

If you have 2 moles of HNO3 that means you have 2 moles of N.

2(14) =

Which is the base in the reaction?

A. H2OB. KOH C. K+

D. H2SO4

Produces OH- ions, or accepts a hydrogen

How many moles of copper are equivalent to 3.44 x 1023 atoms of copper?

A. 0.571 moles

B. 1.75 moles

C. 5.41 x 1021 moles

D. 5.71 x 1022 moles

6.02 x 1023 atoms of copper = 1 mole of copper

Which condition will cause a shift inthe equilibrium of the above reaction?A. Double the concentration of reactants and

productsB. Increase the reaction temperature C. Reduce the concentration of products and

reactants by 10%D. Keep the reaction temperature constant

What is the molar mass of Al(NO3)3?

A. 57 g/mol

B. 103 g/mol

C. 165 g/mol

D. 213 g/mol

1(27) + 3(14) + 9(16) =

What is the mass in grams of one mole of sulfur dioxide (SO2)?

A. 48.1 g

B. 64.1 g

C. 80.1 g

D. 96.1 g

1(32.1) + 2(16) =

Formaldehyde (H2CO) reacts with oxygen to form CO2 and H2O. How many moles of CO2 will be produced from reacting 2 moles of H2CO with oxygen?

A. 1B. 2 C. 4D. 8

H2CO + O2 CO2 + H2O

It is a 1:1 ratio therefore ….

In the combustion of ethane, how many moles of CO2 can be produced from 1.00 mole of C2H6?

A. 0.500 mole

B. 1.00 mole

C. 2.00 moles

D. 4.00 moles

2C2H6 + 7O2 4CO2 + 6H2O

62

262 2

400.1

HmolC

molCOxHmolC

The End

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Molar Relationships