Houston Community College System

Chemistry 1305 Spring 2018 EXAM # 1A

HOUSTON COMMUNITY COLLEGE

CHEM 1305 Name: _____________________

Exam # 1, Chapters 1 – 4 (Corwin 7th Edition) Score:

PART I – Multiple choice: (3 points each)

1) Which of the following is a basic step in the scientific method?

A) Perform an experiment and collect data. B) Analyze experimental data and propose a hypothesis. C) Test a hypothesis and state a theory or law. D) all of the above

2) Which of the following statements is a natural law?

A) The mass of substances, before and after a chemical change, is the same. B) If the volume of a gas doubles, the pressure decreases by a factor of two.

C) The energy derived from a change in mass is found by E = mc2. D) all of the above

3) What is the term for a direct change of state from a gas to a solid?

A. Condensation B. Deposition C. Sublimation D. Vaporization E. None of these

4) Which of the following properties of ethyl alcohol is a physical property?

A. colorless liquid B. density, 0.789 g/mL C. boiling point, 78.5 °C

D. specific heat, 0.511 cal/(g x °C) E. All of these

5) What subject is said to be at the crossroads of biology, physics, and geology?

A) biochemistry B) chemistry C) environmental chemistry D) geochemistry

6) Which of the following properties of gasoline is a chemical property?

A. boiling point, 97 °C B. density, 0.692 g/mL C. burns with air

D. insoluble in water E. colorless liquid

7) What is the term for the inexactness of an instrumental measurement?

A) accuracy B) error C) precision D) uncertainty

8) Which of the following metric rulers has the least uncertainty?

A) Ruler A, ± 1 cm B) Ruler B, ± 0.1 cm C) Ruler C, ± 0.5 cm D) Ruler D, ± 0.05 cm

9) How many significant figures are there in the number 0.04560700?

A) 4 B) 5 C) 7 D) 9

10) Express the number 0.000333 in scientific notation.

A. 333 ⅹ 10-6 B. 3.33 ⅹ 102 C. 3.33 ⅹ 104 D. 3.33 ⅹ 10-4 E. 0.333 ⅹ 10-3

11) Convert 59.4 mi to km. (1 m = 1.094 yd, 1 mi = 1760 yd)

A. 6.5 ⅹ 101 km B. 3.69 ⅹ 101 km C. 9.56 ⅹ 107 km D. 5.43 ⅹ 101 km E. 9.56 ⅹ 101 km

12) Calculate 5.1234 + 0.033 /1.650 and report to the correct number of significant figures.

A. 3.1 B. 3.125 C. 5.143 D. 5.1 E. 3.13

13) Which of the following is an example of a physical change?

A. adding vinegar to baking soda and producing carbon dioxide

B. grinding sucrose crystals and producing powdered sugar C. smoking tobacco and producing smoke and ash

D. digesting starch and producing glucose sugar

E. None of these

14) What is the symbol for the metric unit micrometer?

A) cm B) mm C) Mm D) μm

15) What is the name corresponding to the metric symbol mL?

A) megaliter B) metroliter C) microliter D) milliliter

16) According to the metric system, 1 ________ = 1,000,000 g.

A) Gg B) Mg C) kg D) μg

17) Which of the following laws states that energy cannot be created or destroyed?

A. law of conservation of energy

B. aw of conservation of mass

C. law of conservation of mass and energy

D. law of definite composition

E. None of these

18) Which of the following describes a substance in the gaseous physical state?

A) The substance has a variable shape. B) The substance has a variable volume. C) The substance compresses significantly. D) all of the above

19) What is the term for stored energy that matter possesses related to its position or chemical composition?

A. heat energy B. kinetic energy C. mechanical energy

D. potential energy E. None of these

20) Cyanocobalamin, C63H88CoN14O14P, is vitamin B12. What is the number of atoms in one molecule of vitamin B12?

A. 12 B. 179 C. 180 D. 181 E. None of these

PART II – Show All Your Work: (8 points each) 1) Magnesium is one of the least dense elements (d = 1.74 g/cm3). What is the volume of a 10.0 g sample

of the metal?

2) A piece of tin foil has a volume of 0.645 mm3. If the piece measures 10.0 mm by 12.5 mm, what is the

thickness of the foil in mm?

3) An antifreeze solution freezes at -100 °C. What is the freezing point on the Fahrenheit scale?

4) Liquid krypton boils at 121 K. What is the boiling point on the Celsius scale?

5) A hybrid vehicle has a mileage rating of 22 km/L. What is the gas mileage in miles per gallon? (Given: 1 mi

= 1.61 km, and 1 gal = 3.78L)

BONUS QUESTION – Show All Your Work: (10 points)

Calculate 5.1234 + 0.033 /1.650 and report to the correct number of significant figures.

Soluble Compounds

Insoluble Compounds

Activity Electro-

Series negativity Li H 2.1

K Li 1.0

Ba Na 0.9

Ca B 2.0

Na C 2.5

Mg N 3.0

Al O 3.5

Zn F 4.0

Cr Cl 3.0

Fe

Cd Br 2.8

Co I 2.5

Ni

Sn S 2.5

Pb Se 2.4

H2

Cu

Ag

Hg

Pt

Au

.Ba and ,Hg

,Sr ,Ca ,Pb of those soluble are sulfates All 4)

.Hg and ,Pb ,Ag with combined

when soluble are Ior ,Br ,Cl containing salts All 3)

soluble. are

OHC and ,ClO ,ClO ,NO ,NH containing salts All 2)

soluble. are IA) (Group metals alkali theof compounds All 1)

22

2

222

2

2

2

---

-

232

-

3

-

4

-

34

except

except

.NH andIA Group of those

insoluble, are S and ,SO ,CO ,POcontain that salts All 6)

in water.exist not does ,O ion, oxide The .hydroxides

form water toreact with they dissolve, do oxides

metal When .Ba and ,Sr ,Ca of andIA Group of

those insoluble are oxides and hydroxides metal All 5)

4

-2-2

3

-2

3

-3

4

-2

222

except

except

Constants/ Relationships

density = mass/volume Avogardo’s number = 6.022 x 1023 things/mol ∆E = q + w q = mass x specific heat x ∆t 1 cal = 4.184 J K = °C + 273 °F = (9/5)(°C) + 32 Planck’s constant = h = 6.63 x 10 –34 J•s Speed of light = c = 3.00 x 108m/s

c = 1 J = 1 kg•m2•s-2 RH = 2.18 x 10-18 J

∆E = h

E RH1

ni2

1

n f2

Gas constant = R = 0.0821 L•atm mol-1•K-1

PV = nRT

d = (PM)/(RT)

Molar volume of a gas = 22.4 L at STP

STP = 1 atm and 0°C

1 atm = 760 mm Hg = 760 torr

2.54 cm

specific heat of water = 4.184 J•g-1•°C-1