WBasic Chemistry

Exam 1

100

Significant Digits

Add the following: 1.206 + 2.22 + 1316.3

a) 1319.72

b) 1319.726

c) 1319.7

d) 1319

c) 1319.7

200

What is the percent by mass of nitrogen in magnesium nitrate?

a) 9.44% b) 18.89% c) 64.72% d) 28.00%

Mg(NO₃)₂

18.89% N

(14.00/148.33) x 100 = 18.89

300

The atomic mass of silver is 107.868 amu. There are two naturally occurring isotopes of silver, Ag-107 (106.904 amu) and Ag-109 (108.905 amu). What percentage of naturally occurring silver is the heavier isotope? 

a) 42.5% 

b) 45.4% 

c) 48.2% 

d) 49.8%  

c) 48.2%

400

If 16.0 g of methanol are reacted with an excess of PBr3, how many grams of CH3Br would be formed if there is a 25.0% yield?   

CH3OH(l) + PBr3(l) → CH3Br(l) + H3PO3(l) 

a) 5.92 g

b) 11.9 g

c) 23.7 g

d) 35.6 g

E. 47.4 g

b) 11.9 g

500

How many oxygen atoms are in 121 g of FeSO₄•5H₂O? (molecular weight = 242 g/mol)

a) 1 x 10²³

b) 3 x 10²³

c) 6 x 10²³

d) 3 x 10²⁴

d) 3 x 10²⁴

Exam 2

100

A gaseous compound is 52.14% C, 13.13% H and the rest of the compound is oxygen.

At STP, 325 mL of the gas weighs 0.668 g. What is its molecular formula?

a) C₂H₆O

b) C₃H₆O

c) C₃H₅O

d) C₄H₈O

a) C₂H₆O

200

The ground state electron configuration for Neon?

a) 1s²2s²2p⁶

b) [He]2p⁶

c) 2s²2p⁶

d) 2p⁶

a) 1s²2s²2p⁶

300

The shorthand notation for an orbital with quantum numbers n = 4, l = 3 is 

a) 4p

b) 4d 

c) 3f 

d) 4f 

e) 1s

d) 4f

400

Which of the following is oxidized in the reaction? 

Fe_(s)  +  CuSO_{4 (aq)} --> FeSO_{4 (aq)} + Cu_(s)

a) Cu

b) Fe

c) S

d) O

b) Fe

500

Given the following data: 

2O_3 (g) ---> 3O_{2 (g)}                           ΔH = -427 kJ

O_2 (g) ---> 2O _(g)                              ΔH = +495 kJ

NO_(g) + O_{3 (g) --->} NO_{2 (g)} + O_{2 (g)}      ΔH = -199 kJ

Calculate the ΔH for the reaction 

NO_(g) + O _{(g) --->} NO_{2 (g)} 

ΔH = -233 kJ

Exam 3

100

What is the hybridization of nitrogen in the molecule: 

Cl₂C=N-CH=CH₂

a) sp

b) sp²

c) sp³

d) sp³d

b) sp²

200

How many sigma and pi bonds does acetic acid (CH₃COOH) contain?

a) 4 sigma bonds and 1 pi bond

b) 7 sigma bonds and 1 pi bond

c) 5 sigma bonds and 2 pi bond

d) 6 sigma bonds and 2 pi bond

b) 7 sigma bonds and 1 pi bond

300

A sample of thorium-232 (Th) decays via the following sequence of emissions: a, B, B, a. What is the product at the end of these four decays?

a) uranium-240

b) radium-224

c) polonium-240

c) radon-224

b) radium-224

400

Which of the following has the strongest chemical bonds? 

He₂⁺    He₂    He₂²⁺

a) He₂⁺

b) He₂

c) He₂²⁺

d) they all about the same

c) He₂²⁺

500

A molecule has the following properties:

- The molecule contains no sp hybridized orbital

- The molecule contains at least one sp² hybrid orbital

- The molecule contains no sp³ hybrid orbital

a) CH₃COOH

b) CH₄

c) CH₂O

d) HCN

c) CH₂O