CHEM 101-Introductory Chemistry I QUIZ 4

(Each is worth 5 – Circle the letter for the correct answer)

1. Chlorthalidone (C14H11ClN2O4S) is a theraputic agent for the treatment of high blood pressure in humans. What is the molar mass of chlorthalidone to the nearest tenth?

b. 338.6 g

2. The number of sulfur atoms in 96 grams of sulfur is

d. 1.8 x 1024

3. 2.00 moles of CO2

d. contains 1.20 x 1024 molecules of CO2

4. What is the empirical formula for a hydrocarbon that analyzes as 92.3 percent Carbon and 7.7 percent hydrogen?

a. CH

Chemistry 101 Spring 2020

5. The formula for ibuprofen is C13H18O2. How many moles of ibuprofen are present in a 200 mg tablet?

b. 9.695 x 10-4 mol

6. Complete the following table. This is worth 12.

Compound

Mass

Moles

Number of molecules

Number of atoms

H20

112 kg

6216.945

3.744*10^27

6.01*10^23

SO2

6.33 mg

0.00633

3.8*10^25

N2

9.67g

0.345

5.73*1025

1.205*10^24

C2H5OH

137.67

2.989

1.8 x 1024

6.022*10^23

7. Putrescine is a compound that is partially responsible for the rotten smell of decaying flesh. It consists of 54.50% carbon, 13.73% hydrogen, and 31.77% nitrogen. What is the empirical formula of putrescine?

e. C2H6N

8. The empirical formula of a compound is CH. If the molar mass of this compound is 78.0 grams then the molecular formula is

c. C6H6

9. What is the empirical formula for octane, C8H18?

b. C4H9

10. Calculate the mass percent composition of each element in the compound, Tin(IV) sulfate?

mass of Tin Sn(SO4)2=118.71+32*2+16*8=310.71g/mole

mass percent

Sn=1*118.71*100/310.71=38.2%

S=2*32*100/310.71=20.6%

O=8*16*100/310.71=41.2%

11. How many moles of oxygen in 13.3 moles of sulfuric acid, H2SO4?

(15.9994*4)/98.0784=65.3%

65.3%*13.3=8.68 mole of oxygen

12. Lithium carbonate is used in the treatment of mental illnesses such as bipolar disorder. How many grams of lithium are contained in a 1.50 gram dose of lithium carbonate?

d. 0.282 g

13. Nicotine, a stimulant found in tobacco, is a compound that analyzes as 74.03% carbon, 8.7% hydrogen, and 17.27% nitrogen. The molar mass of nicotine is 162.26 g/mol. Calculate the empirical formula and the molecular formula for nicotine?

74.03 g C *(1molC/12g) = 6.164 mol C 8.70 g H *(1mol H/1g) = 8.70 molH 17.27 g N *(1mol N/14g) = 1.23 mol N 6.164/1.23 = 5.01 C 8.70/1.23 = 7.07 H 1.23/1.23 = 1 N empirical formula C5H7N