CHEM 133 Week 8 Midterm Exam

CHEM 133 Week 8 Midterm Exam | American Public University System

Question 1 of 35

A piece of antimony with a mass of 17.41 g is submerged in 46.3 cm3 of water in a graduated cylinder. The water level increases to 48.9 cm3. The correct value for the density of antimony from these data is:

•              

A.

2.81 g/cm3

•              

B.

6.697 g/cm3

•              

C.

0.356 g/cm3

•              

D.

6.7 g/cm3  

•              

E.

0.15 g/cm3

Question 2 of 35

How many square kilometers are equivalent to 28.5 cm2?

•              

A.

2.85 × 10–4 km2

•              

B.

2.85 × 10–9 km2

•              

C.

285 km2

•              

D.

2.85 × 10–6 km2

Question 3 of 35

The winner of the men's 1500-meter speed skating event at a recent Winter Olympics had a time of 1:45.57. Assuming that the distance was measured accurately to five significant figures, what was the skater's average speed in miles per hour?

•              

A.

51.151 mi/hr

•              

B.

61.826 mi/hr

•              

C.

31.785 mi/hr

•              

D.

38.418 mi/hr

Question 4 of 35

What is the volume, in cubic centimeters, of a brick that is 4.0 in × 2.7 in × 8.0 in?

•              

A.

53 cm3

•              

B.

5.3 cm3

•              

C.

1.4 × 103 cm3

•              

D.

4.8 × 102 cm3

•              

E.

87 cm3

Question 5 of 35

Substances with constant composition that can be broken down into elements by chemical processes are called:

•              

A.

Solutions

•              

B. Heterogeneous mixtures

•              

C.

Compounds

•              

D.

Mixtures

•              

E.

Atoms

Question 6 of 35

A sample of chemical X is found to contain 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen. The law of definite proportion would predict that a 67 gram sample of chemical X should contain how many grams of carbon?

•              

A.

5.0 g

•              

B.

15 g

•              

C.

10. g

•              

D.

6.7 g

•              

E. 19 g

Question 7 of 35

What is the chemical symbol for an atom that has 29 protons and 36 neutrons?

•              

A.

Cu

•              

B.

Tb

•              

C.

Kr

•              

D.

N

Question 8 of 35

Name the following compound: CuSO4

•              

A. Copper (IV) sulfate

•              

B.

Copper (II) sulfite

•              

C.

Copper (I) sulfate

•              

D.

Copper sulfate

•              

E.

Copper (II) sulfate

Question 9 of 35

•              

A.

N2O3

•              

B.

N3O2

•              

C.

N(OH)3

•              

D.

(NO3)2

Question 10 of 35

18O2- and 20Ne have the same number of

•              

A.

electrons + neutrons

•              

B.

protons

•              

C.

electrons

•              

D.

neutrons

Question 11 of 35

How many Cl atoms are in 0.0728 g of PCl3?

•              

A.

4.38 x 1022 Cl atoms

•              

B.

1.32 x 1023 Cl atoms

•              

C.

3.19 x 1020 Cl atoms

•              

D.

9.58 x 1020 Cl atoms

•              

E.

1.81 x 1024 Cl atoms

Question 12 of 35

2.0/ 2.0 Points

Naturally occurring copper exists in two isotopic forms: 63Cu and 65Cu. The atomic mass of copper is 63.55 amu. What is the approximate natural abundance of 63Cu?

•              

A.

63%

•              

B.

90%

•              

C.

70%

•              

D.

50%

•              

E. 30%

Question 13 of 35

If 0.274 moles of a substance weighs 62.5 g, what is the molar mass of the substance, in units of g/mol?

•              

A.

2.17 × 102 g/mol

•              

B.

2.28 × 102 g/mol

•              

C.

4.38 × 10–3 g/mol

•              

D.

1.71 × 101 g/mol

•              

E.

6.02 x 1023 g/mol

Question 14 of 35

0.0/ 2.0 Points

1.00 mole of O2 contains the same number of molecules as

•              

A.

1.00 mole of CH3CO2H.

•              

B.

All of the choices

•              

C.

0.667 mole of O3.

•              

D.

2.00 mole of CH3CH2OH.

Question 15 of 35

What volume of 18 M sulfuric acid must be used to prepare 1.80 L of 0.215 M H2SO4?

•              

A.

0.39 mL

•              

B.

22 mL

•              

C.

2.2 x 103 mL

•              

D.

7.0 mL

•              

E.

4.3 mL

Part 5 of 11 - 133 MC Chapter 04               

Question 16 of 35

A 57.17 g sample of Ba(OH)2 is dissolved in enough water to make 1.800 L of solution. How many mL of this solution must be diluted with water in order to make 1.000 L of 0.100 M Ba(OH)2?

•              

A.

539 mL

•              

B.

185 mL

•              

C.

18.5 mL

•              

D.

300. mL

•              

E.

3.34 mL

Feedback:

See Chapter 04

Question 17 of 35

If the percent yield for the following reaction is 75.0%, and 45.0 g of NO2 are consumed in the reaction, how many grams of nitric acid, HNO3(aq) are produced?

3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g)

•              

A.

41.1 g

•              

B.

54.8 g

•              

C.

30.8 g

•              

D.

69.3 g

Feedback:

See Chapter 04

Question 18 of 35

A 6.82 g sample of potassium chlorate was decomposed according to the following equation:

2 KClO3 → 2 KCl + 3 O2

How many moles of oxygen are formed?

•              

A.

0.0557 mol

•              

B.

0.0371 mol

•              

C.

0.0835 mol

•              

D. none of these choices

•              

E.

2.67 mol

Feedback:See Chapter 04

Question 19 of 35

Which of the following will occur when solutions of CuSO4(aq) and BaCl2(aq) are mixed?

•              

A.

A precipitate of BaSO4 will form; Cu2+ and Cl– are spectator ions.

•              

B.

A precipitate of CuCl2 will form; Ba2+ and SO42– are spectator ions.

•              

C.

A precipitate of BaCl2 will form; Cu2+ and SO42– are spectator ions.

•              

D.

A precipitate of CuSO4 will form; Ba2+ and Cl– are spectator ions.

•              

E. No precipitate will form.

Feedback:See Chapter 04

Question 20 of 35

Aluminum metal reacts with iron(II) sulfide to form aluminum sulfide and iron metal. What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

•              

A.

2

•              

B.

4

•              

C.

3

•              

D.

1

Feedback:

See Chapter 04

Part 6 of 11 - 133 MC Chapter 07                10.0/ 10.0 Points

Question 21 of 35

A common way of initiating certain chemical reactions with light involves the generation of free halogen atoms in solution.

For the reaction,

Cl2(g) → 2Cl(g)        ΔH = 242.8 kJ/mol

what is the longest wavelength of light that will produce free chlorine atoms in solution?

•              

A.

465.2 nm

•              

B.

246.3 nm

•              

C.

698.6 nm

•              

D.

349.3 nm

•              

E.

492.6 nm

Feedback:

See Chapter 06

Question 22 of 35

What is the de Broglie wavelength of an electron (m = 9.11 × 10-31 kg) moving at a velocity of 3.0 × 107 m/s?

•              

A.

2.4 × 10-11 m

•              

B.

1.1 × 10-4 m

•              

C.

3.9 × 10-12 m

•              

D.

3.3 × 10-8 m

Question 23 of 35

For an orbital, a node is

•              

A.

the midpoint of the orbital.

•              

B.

a surface where there is a maximum probability of finding the electron.

•              

C.

a surface where there is no chance of finding the electron.

•              

D.

a surface inside which there is a 90% chance of finding the electron.

Question 24 of 35

What is the wavelength of light that is emitted when an excited electron in the hydrogen atom falls from

n = 5 to n = 1?

•              

A.

2.09 x 10–18 m

•              

B.

9.12 x 10–8 m

•              

C.

9.50 x 10–8 m

•              

D.

1.05 x 107 m

Question 25 of 35

What is the wavelength of radiation that has a frequency of 5.39 × 1014 s–1?

•              

A.

6180 nm

•              

B.

556 nm

•              

C.

618 nm

•              

D.

1.80 × 10–3 nm

•              

E.

1.61 × 1023 nm

Part 7 of 11 - 133 SA Chapter 01 6.0/ 10.0 Points

Question 26 of 35

A metallic cube has a mass of 9.0 g and a side of 3.00 cm.

What is the density of the metal piece in oz/in3 ?

16 oz = 1 lb

2.2 lb = 1 kg

Comment:did not show where these numbers came from

Question 27 of 35

5.0/ 5.0 Points

The density of lead is 11.4 g/cm3. Convert the density to lb/ft3.

1 lb = 454.55 g

1 ft = 12 in

1 in = 2.54 cm

11.4g x 1k x 2.205lb x 2.54cm x 12 in x 12 in x 12 in 1 cm3 x 1000g x 1kg x 1 in x 1in x 1in x 1 foot x 1 foot x 1 foot multiply and then cancel all like terms=711,800.5727831lbs/1000feet3  once divided this = 711.8 rounded to 712lbs/feet3

Question 28 of 35

Lithium, is used in dry cells and storage batteries and in high temperature lubricants, it has two naturally occurring isotopes, 6Li and 7Li. Calculate the atomic mass of lithium.

 isotope                6Li           7Li

isotopic mass(amu)         6.01521 7.016003

abundance(%)  7.50        92.50

6.015121 x + 7.016003 ( 100-x) / 100 = 6.9409 6.016121 x + 701.6003 - 7.016003x = 694.09 - 0.99982 x = - 7.5103 x = 7.5 %

Question 29 of 35

4.0/ 5.0 Points

Name the following compounds:

a. HCN

b. P2O5

c. Pb(NO3)2

d. Ba(OH)2

e. SnCl2

a.hydrogen cyanide

b.phosphoruspentoxide

c.lead (II) nitrate

d.barium hydroxide

e.tin (II) chloride

Feedback:See Chapter 02

Comment:diphosphorus

Part 9 of 11 - 133 SA Chapter 03 5.0/ 10.0 Points

Question 30 of 35

What is the molarity of a solution that contains 8.4 g NaOH in 240.0 mL of solution.

8.4g/40g=.21mol 240ml=.24L .21mol/.21L=.875mol/L

Feedback:See Chapter 03

Question 31 of 35

If 30.0 mL of 0.15 M Ba(OH)2 was needed to neutralize 50.0 mL of an H3PO4 solution. What is the concentration of the original H3PO4 solution?

0.06m

Feedback:See Chapter 03

Question 32 of 35

When 0.6943 g of a compound is subjected to combustion analysis it produced 1.471 g CO2 and 0.391 g H2O. What is its empirical and molecular formula if its molar mass is 172 g/mol if the compound is composed of only carbon, hydrogen, and oxygen.

empirical C2H30

molecular C8H1204

Feedback:See Chapter 04

Comment:show work

Question 33 of 35

For the following reaction:

K2CO3 (aq) + H2SO4 (aq) →

a) Write the complete ionic reaction equation.

b) Write the net ionic reaction equation.

Question 34 of 35

Calculate the wavelength (in nm) for the electronic transition from n = 3 to n = 5 in the hydrogen atom.

Question 35 of 35

For Bromine atom:

a) Determine the total number of unpaired electrons.

b) Write the electron configuration.

c) Identify the core electrons and the valence electrons.