MOL Concept MOL Concept WarmupsWarmups

1. The gram-formula mass of a compound 1. The gram-formula mass of a compound is 48 grams. The mass of 1.0 mole of this is 48 grams. The mass of 1.0 mole of this compound is – compound is –

A. 1.0 gA. 1.0 g

B. 4.8 gB. 4.8 g

C. 48 gC. 48 g

D. 480 g D. 480 g

AnswerAnswer

C is the correct answer.C is the correct answer.

2. How many moles are in 59.6 grams of 2. How many moles are in 59.6 grams of BaSOBaSO44??

A) 0.256 moleA) 0.256 mole

B) 3.91 molesB) 3.91 moles

C) 13.9 molesC) 13.9 moles

D) 59.6 moles D) 59.6 moles

AnswerAnswer

A is the correct answer.A is the correct answer.

3. 3. How many molecules are contained in How many molecules are contained in

55.0 grams of H2SO4?55.0 grams of H2SO4?

A) 0.561 moleculesA) 0.561 molecules

B) 3.93 moleculesB) 3.93 molecules

C) 3.38 X 10C) 3.38 X 102323 molecules molecules

D) 2.37 X 10D) 2.37 X 102424 molecules molecules

AnswerAnswer

C is the correct answer.C is the correct answer.

4. If a sample of magnesium has a mass of 4. If a sample of magnesium has a mass of 60. grams, how many moles of 60. grams, how many moles of magnesium does the sample contain?magnesium does the sample contain?

A) 1.1 molesA) 1.1 moles

B) 1.2 molesB) 1.2 moles

C) 2.0 molesC) 2.0 moles

D) 2.5 molesD) 2.5 moles

AnswerAnswer

D is the correct answer.D is the correct answer.

5. Analysis shows a compound to be, by mass, 5. Analysis shows a compound to be, by mass, 43.8% N, 6.2% H, and 50.0% O. Which is a 43.8% N, 6.2% H, and 50.0% O. Which is a possible molecular formula for the possible molecular formula for the compound?compound?

A) NHA) NH44NONO22

B) NHB) NH44NONO33

C) NHC) NH33OHOH

D) ND) N22OHOH

AnswerAnswer

A is the correct answer.A is the correct answer.

6. A compound has an empirical formula of 6. A compound has an empirical formula of CHCH22O and a molecular mass of 180 grams. O and a molecular mass of 180 grams. What is the compound’s molecular formula?What is the compound’s molecular formula?

A) CA) C33HH66OO33

B) CB) C66HH1212OO66

C) CC) C66HH1111OO77

D) CD) C1212HH2222OO1111

AnswerAnswer

B is the correct answer.B is the correct answer.

7. What is the percent by mass of 7. What is the percent by mass of iron in the compound Feiron in the compound Fe22OO33??

A) 70 %A) 70 %

B) 56 %B) 56 %

C) 48%C) 48%

D) 30 % D) 30 %

AnswerAnswer

A is the correct answer.A is the correct answer.

8. What is the percent composition by mass 8. What is the percent composition by mass of sulfur in the compound MgSOof sulfur in the compound MgSO44 (gram- (gram-formula mass = 120. grams per mole)?formula mass = 120. grams per mole)?

A. 20%A. 20%

B. 27%B. 27%

C. 46%C. 46%

D. 53%D. 53%

AnswerAnswer

B is the correct answer.B is the correct answer.

9. Given the balanced equation representing a 9. Given the balanced equation representing a reaction:reaction:

2H2H22+ O+ O22→ 2H→ 2H22OO

What is the mass of HWhat is the mass of H22O produced when 10.0 O produced when 10.0 grams of Hgrams of H22 reacts completely with 80.0 reacts completely with 80.0 grams of Ograms of O22??

A. 70.0 gA. 70.0 g

B. 90.0 gB. 90.0 g

C. 180. gC. 180. g

D. 800. GD. 800. G

AnswerAnswer

B is the correct answer.B is the correct answer.

10. Given two formulas representing the same 10. Given two formulas representing the same compound:compound:

Formula A Formula BFormula A Formula B

CHCH33CC22HH6 6 CHCH66CC44HH1212

Which statement describes these formulas:Which statement describes these formulas:A. Formulas A and B are both empirical.A. Formulas A and B are both empirical.B. Formulas A and B are both molecular.B. Formulas A and B are both molecular.C. Formula A is empirical, and formula B is C. Formula A is empirical, and formula B is

molecular.molecular.D. Formula A is molecular, and formula B is D. Formula A is molecular, and formula B is

empirical.empirical.

AnswerAnswer

C is the correct answer.C is the correct answer.

11. The sum of the atomic masses of the 11. The sum of the atomic masses of the

atoms in one molecule of Catoms in one molecule of C33HH66BrBr22is is the– the–

A. formula massA. formula mass

B. isotopic massB. isotopic mass

C. percentage abundanceC. percentage abundance

D. percentage compositionD. percentage composition

AnswerAnswer

A is the correct answer.A is the correct answer.

12. 12. The percent composition by mass of nitrogen The percent composition by mass of nitrogen in NHin NH44OH (gram-formula mass = 35 OH (gram-formula mass = 35

grams/mole) is equal tograms/mole) is equal to – –

A. 4/35 X 100A. 4/35 X 100

B. 14/35 X 100B. 14/35 X 100

C. 35/14 X 100C. 35/14 X 100

D. 35/4 X 100D. 35/4 X 100

AnswerAnswer

B is the correct answer.B is the correct answer.

13. Given the balanced equation representing a 13. Given the balanced equation representing a reaction:reaction:

2NaCl( ) →2Na( ) + Clℓ ℓ2NaCl( ) →2Na( ) + Clℓ ℓ 22(g)(g)

A 1170. gram sample of NaCl( ) completely reacts, ℓA 1170. gram sample of NaCl( ) completely reacts, ℓproducing 460. grams of Na( ). What is the total ℓproducing 460. grams of Na( ). What is the total ℓmass of Clmass of Cl22(g) produced?(g) produced?

A 355 gA 355 g

B 710. gB 710. g

C. 1420. gC. 1420. g

D. 1630. gD. 1630. g

AnswerAnswer

B is the correct answer.B is the correct answer.

14. The gram-formula mass of NO14. The gram-formula mass of NO22 is is defined as the mass of –defined as the mass of –

A. one mole of NOA. one mole of NO22

B. one molecule of NOB. one molecule of NO22

C. two moles of NOC. two moles of NO

D. two molecules of NO D. two molecules of NO

AnswerAnswer

A is the correct answer.A is the correct answer.

15. Given the balanced equation representing a 15. Given the balanced equation representing a reaction:reaction:

CaO(s) + COCaO(s) + CO22(g) →CaCO(g) →CaCO33(s) + heat(s) + heat

What is the total mass of CaO(s) that reacts What is the total mass of CaO(s) that reacts completely with 88 grams of COcompletely with 88 grams of CO22(g) to (g) to produce 200. grams of CaCOproduce 200. grams of CaCO33(s)?(s)?

A. 56 gA. 56 g

B. 88 gB. 88 g

C. 112 gC. 112 g

D. 288 gD. 288 g

AnswerAnswer

C is the correct answer.C is the correct answer.

16. Which formula is both a molecular 16. Which formula is both a molecular and an empirical formula?and an empirical formula?

A) A) CC66HH1212OO66

B) B) CC22HH44OO22

C) C) CC33HH88OO

D) D) CC44HH88

AnswerAnswer

C is the correct answer.C is the correct answer.