CHEM 200 EXAM 1: JULY 2, 1998--you can keep these pages...please turn in the op-scan sheet

1. Monatomic ions formed from lithium, magnesium, aluminum, fluorine (as in fluoride), and oxygen (as in oxide) contain what charge?

(a) +1, +2, +3, -1, and -2, respectively; (b) +1, +2, +2, -1, and -2, respectively; (c) +1, +2, +3, -1, and -1, respectively; (d) +1, +3, +3, -1, and -2, respectively; and (e) none of these.

2. The formula for the compound ammonium carbonate contains how many hydrogen atoms?

(a) 12; (b) 14; (c) 8; (d) 10; (e) 6.

3. Consider the following two statements and select the best answer:

(i.) the molar mass of iron is 55.85 g/mol;
(ii.) the molar mass of water is 18.02 g/mol

(a) i. and ii. are both true; (b) i. and ii. are both false; (c) i. is true and ii. is false; (d) i. is false and ii. is true; (e) The Spice Girls are better than the Beatles.

4.How many grams of carbon are present in 16.55 grams of glucose (C6H12O6)?

(a) 3.32 g; (b) 4.42 g; (c) 5.52 g; (d) 6.62 g; (e) none of these.

5. When octane (C8H18) is allowed to with molecular oxygen, it forms carbon dioxide and water. Write and balance the chemical equation that describes the above reaction, and then answer the following question. If one mole of octane is allowed to react with molecular oxygen, use your balanced equation to state how many moles of water will form...

(a) 1 mole of water; (b) 3 moles of water; (c) 5 moles of water; (d) 7 moles of water; (e) none of these.

6. Consider the following balanced equation:

2 Cu2S (s) + 3O2 (g) ---> 2Cu2O (s) + 2SO2 (g)

How many kilograms of oxygen are required to form 2.86 kg copper (I) oxide?

(a) 0.96 kg O2; (b) 2.96 kg O2; (c) 4.96 kg O2; (d) 6.96 kg O2; (e) none of these.

7. Consider the following balanced equation:

2 N2H4 (l) + N2O4 (l) ---> 3N2 (g) + 4H2O (g)

How many grams of nitrogen gas form when exactly 100 g N2H4 and 200 g N2O4 are mixed?

(a) 131 kg N2; (b) 262 kg N2; (c) 393 kg N2; (d) 474 kg N2; (e) none of these.

8. How many grasm of solute are in 1.75 L of a 0.46 M sodium monohydrogen phosphate solution?

(a) 114 g Na2HPO4; (b) 214 g Na2HPO4; (c) 314 g Na2HPO4; (d) 414 g Na2HPO4; (e) none fo these.

9. The reaction X + Y ---> Z is an example of what kind of reaction?

(a) decomposition reaction; (b) combination reaction; (c) single displacement reaction; (d) double displacement reaction; (e) none of these

10. Consider the following two statements and select the best answer:

(i.) in a precipitation reaction, two soluble ionic compounds react to form an insoluble product;
(ii.) the combined effect of water's shape and its polar covalent bonds makes water a polar molecule

(a) i. and ii. are both false; (b) i. and ii. are both true; (c) i. is true and ii. is false; (d) i. is false and ii. is true; (e) wealthy folks make their summer homes in Carbondale because of the cool and dry summers.

11. An ionic compound that results from the reaction of an acid and a base is called a salt.

(a) false; (b) true

12. You perform an acid-base titration to standardize an HCl solution by placing 50.00 mL HCl in a flask with a few drops of indicator solution. You fill the buret with 0.1524 M NaOH. The initial buret reading is 0.55 mL; at the end point, the buret reading is 33.87 mL. What is the concentration of the HCl solution? (choose the closest answer)

(a) 0.4016 M HCl; (b) 0.1016 M HCl; (c) 0.2016 M HCl; (d) 0.6016 M HCl; (e) 0.8016 M HCl

13. The oxidation numbers for sulfur and oxygen in sulfur trioxide are...

(a) + 4 and -2, respectively; (b) + 4 and -4, respectively; (c) + 2 and -2, respectively; (d) + 6 and
-6, respectively; (e) none of these

14. A 10 M solution of NaCl contains how many liters of solution?

(a) more information is needed to solve the problem; (b) 10 L; (c) 20 L; (d) 14 L; (e) 2 L

15. Consider the following two statements and select the best answer:

(i.) gases are highly compressible;
(ii.) gases have high viscosities

(a) i. and ii. are both false; (b) i. and ii. are both true; (c) i. is false and ii. is true; (d) i. is true and ii. is false; (e) the Chicago Cubs will win the World Series this year.

16. How many torr are in two atmospheres of pressure?

(a) 1440 torr; (b) 720 torr; (c) 1720 torr; (d) 2720 torr; (e) none of these.

17. A sample of trapped air occupies 24.8 cm3 at 1.12 atm. If the pressure of the air suddenly increases to 2.64 atm...assuming constant temperature, what is the new volume of air (in L)?

(a) 2.28 L; (b) 3.69 L; (c) 0.0248 L; (d) 7.05 L; (e) none of these.

18. The volume of one mole of an ideal gas, at standard conditions...is...

(a) 0.147 L; (b) 22.4 L; (c) 158.2 L; (d) 760 L; (e) none of these.

19. A tank with a fixed volume of 438 L is filled with 0.885 kg O2. Calculate the pressure of the oxygen at 21oC (HINT: R = 0.0821 atm . L / mol. K)?

(a) 14 L; (b) 12 atm; (c) 1.53 L; (d) 1.53 atm; (e) none of these

20. What mass of potassium chloride forms when 5.25 L chlorine gas at 0.950 atm and 293 K reacts with 17.0 g potassium?

HINT: the balanced equation is 2 K (s) + Cl2 (g) ---> 2KCl (s)

(a) 30.9 g K; (b) 130.9 g K; (c) 230.9 g K; (d) 330.9 g K; (e) none of these

CHEM 200 EXAM #2

1 and 2. A 15.0 L container holds 0.580 kg Cl2 gas at 200o C. Calculate the pressure using the van der Waals equation.

HINT: for chlorine gas--a=6.49 atm .L2/mol2 and b=0.0562 L/mol

while R = 0.0821 L . atm / K mole

and the van der Waals equation is [P + n2a/V2] [V - nb] = nRT

a. 19.9 atm
b. 78.4 atm
c. 34.7 atm
d. 4.77 atm
e. none of these

select your answer and blacken that letter for numbers 1 and 2. In other words, this problem is worth ten points.

3. For a reaction in which the sign of DH is negative, that reaction is

a. exothermic
b. endothermic
c. more information is needed
d. could be either depending on the circumstances
e. none of these

4. How much heat is needed to raise the temperature of 250 g of copper from 25oC to 300oC? The specific heat capacity of copper is 0.387 J/g .K

a. 1.33 x 104 joules
b. 2.66 x 104 joules
c. 3.99 x 104 joules
d. 5.78 x 104 joules
e. none of these

5. A 25.64 g sample of an unknown solid was heated in a tube to 100.00oC in boiling water and carefully added to a coffee-cup calorimeter containing 100.00 g water. The water temperature increased from 25.10oC to 28.49oC. What is the specific heat capacity of the solid? The specific heat capacity of liquid water is 4.184 J/g.K.

a. 0.387 J/g.K
b. 0.774 J/g.K
c. 1.237 J/g.K
d. 4.897 J/g.K
e. none of these

6. Consider the following two statements:

i. an element in its standard state is assigned a DHof of 0.
ii. most compounds have positive DHof

a. both statement are true
b. both statements are false
c. i is true; ii is false
d. i is false; ii is true

7. When one mole of a substance melts, the enthalpy changed is the heat of

a. vaporizatoin
b. fusion
c. formation
d. combustion

8. Which has the greatest heat capacity?

a. gold
b. copper
c. steel
d. water
e. glass

9. Consider the following two statements:

i. visible light has longer wavelength than x-ray radiation
ii. microwaves have a greater frequency than visible light

a. both statement are true
b. both statements are false
c. i is true; ii is false
d. i is false; ii is true

10. When an electron is in an orbit closest to the nucleus (n = 1), we say that the atom is in its lowest (first) energy level. We also say that the atom is in its

a. excited state
b. ground state

11. Mass and energy are related to each other...and the de Broglie wavelength l for an object can be determined if its mass (m) and velocity (u) are known...according to the equation l = h / m.u where h is Planck's constant...6.626 x 10-31kg . m2 / s

Calculate the deBroglie wavelength (in meters) for a baseball with a mass of 142 g that is moving at a velocity of 25 meters per second.

a. 2 x 10-23 m
b. 2 x 10-28 m
c. 2 x 10-34 m
d. 2 x 10-63 m
e. 2 x 10-163 m

12. How many different ml values (magnetic quantum numbers) are there when l, the azimuthal quantum number, is equal to 2?

a. 1
b. 2
c. 3
d. 4
e. 5

13. When l , the magnetic quantum number, is equal to 2, what designation is given to the sublevel?

a. s
b. p
c. d
d. f
e. none of these

14. There are how many different orientations in space for d orbitals? This is the same as asking, within a given horizontal row, how many d orbitals are there?

a. 1
b. 2
c. 3
d. 4
e. 5

15. Each orbital can contain how many electrons?

a. up to and including two
b. up to and including three
c. up to and including four
d. up to and including five
e. none of these
16. How many 3p electrons are present in a neutral atom of sulfur?

a. 1
b. 2
c. 3
d. 4
e. 5

17. How many 3d electrons are present in a neutral atom of copper?

a. 2
b. 4
c. 6
d. 8
e. 10

18. Generally speaking, for the main group elements (i.e. all of the "A" elements in the periodic chart), within a given period, as you move across a row from left-to-right, the atomic radius...

a. increases
b. decreases
c. stays the same

19. Generally speaking, for the main group elements (i.e. all of the "A" elements in the periodic chart), within a given period, as you move across a row from left-to-right, the ionization energy...

a. increases
b. decreases
c. stays the same

20. A bromide ion is isoelectronic with

a. krypton
b. argon
c. oxygen
d. neon
e. none of these

CHEM 200 EXAM #3...turn in only the op-scan sheet

1. A Cu+ ion is...
a. diamagnetic and possesses nine 3d electrons
b. paramagnetic and possesses nine 3e electrons
c. diamagnetic and possesses ten 3d electrons
d. paramagnetic and possesses ten 3d electrons
e. none of these

2. Consider statements i. and ii. below, and select the best answer...

i. a sodium ion is larger than a sodium atom
ii. a chloride ion is smaller than a chlorine atom

a. i. and ii. are both false
b. i. and ii. are both true
c. i. is true; ii. is false
d. i. is false; ii. is true

3. The bonding that exists in sodium chloride is an example of...

a. covalent bonding
b. metallic bonding
c. ionic bonding
d. none of these

4. How many 2s electrons are present in a single lithium ion (Li+)?

a. one
b. zero
c. three
d. two
e. none of these

5. How many unshared pairs of valence electrons exist in a single molecule of nitrogen (N2)?

a. two
b. three
c. four
d. five
e. none of these
6. Consider the following two statements and then select from a. through d. that follow:

i. a carbon-carbon single bond is shorter than a carbon-carbon double bond
ii. a carbon-carbon single bond is weaker than a carbon-carbon double bond

a. both statement are true
b. both statements are false
c. i is true; ii is false
d. i is false; ii is true

7. The bond that connects iodine atoms in I2 (molecular iodine) is [longer or shorter] than the bond that connects chlorine atoms in Cl2 (molecular chlorine).

a. shorter
b. longer

8. In a carbon-fluorine bond, which atom has a partial negative charge?

a. the carbon atom
b. the fluorine atom

9. A single molecule of NF3 contains how many unshared pairs of valence electrons?

a. ten
b. nine
c. eleven
d. twelve
e. none of these

10. The nitrate ion (NO3­) has how many equivalent resonance structures?

a. three
b. four
c. two
d. one
e. none of these

11. A single molecule of NO2, which is uncharged, contains how many unshared pairs of valence electrons?

a. four
b. five
c. six
d. seven
e. none of these

12. The O-C-O bond angle in carbon dioxide is...

a. 180o
b. 120o
c. 90o
d. 45o
e. none of these

13. The molecule SnCl2 is what shape?

a. linear
b. trigonal planar
c. bent
d. trigonal pyramidal
e. tetrahedral

14. The molecule NH3 is what shape?

a. octahedral
b. trigonal planar
c. trigonal pyramidal
d. bent
e. tetrahedral

15. The molecule SF6 is what shape?

a. linear
b. octahedral
c. trigonal pyramidal
d. square planar
e. tetrahedral

16. Consider the following two statements:

i. ammonia is a polar molecule
ii. boron trifluoride is a polar molecule

Which of the following is valid?

a. both statement are true
b. both statements are false
c. i is true; ii is false
d. i is false; ii is true

17. How many p bonds are present in a single molecule of methane?

a. 0
b. 1
c. 2
d. 3
e. 4

18. Do hydrogen bonds exist in a solution of methanol molecules?
HINT: methanol's molecular formula is CH3OH

a. yes
b. no

19 and 20. How much heat is needed to raise the temperature of ten moles of water to 130oC...if the initial temperature of the water is -40oC?

pick the closest answer

a. 142 kJ
b. 396 kJ
c. 468 kJ
d. 648 kJ
e. 970 kJ

THIS QUESTION IS WORTH TEN POINTS...fill in the circles in both number 19 and number 20 with your answer to this question.