CHEMISTRY 101Fall 2009

Hour Exam IPage No. 1

CHEMISTRY 101Name ______

Hour Exam I

September 22, 2009Signature ______

Adams/Sperling

Section______

"To repeat what others have said, requires education; to challenge it, requires brains."

--Mary Pettibone Poole

This exam contains 17 questions on 6 numbered pages. Check now to make sure you have a complete exam. You have one hour and fifteen minutes to complete the exam. Determine the best answer to the first 15 questions and enter these on the special answer sheet. Also, circle your responses in this exam booklet. Show all of your work and provide complete answers to questions 16 and 17.

1-15(30 pts.)______

16 (12 pts.)______

17 (18 pts.)______

Total (60 pts)______

Useful Information:

Always assume ideal behavior for gases (unless explicitly told otherwise).

PV = nRT

R = 0.08206 L•atm/mol•K

K = C + 273

Avogadro’s number = 6.022 × 1023

STP = standard temperature and pressure = 0C and 1.00 atm

Assume atmospheric pressure is 1.00 atm (unless explicitly told otherwise).

1 lb = 453.59 g

1.How many of the following are true regarding the ion ?

  1. The number of neutrons is 78.
  2. The ion contains more protons than electrons.
  3. The mass number is 133.
  4. The ion is an alkali metal.

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

2.You are conducting an experiment where you need the volume of a box. You take the length, height, and width measurements and then multiply the values together to find the volume. You report the volume of the box as 0.310 m3. If two of your measurements were 0.7120 m and 0.52458 m, what was the other measurement?

a)0.83 mb)0.829 mc)0.8300 md)0.8299 me)0.830 m

3.A compound has the general formula X2O, with X representing an unknown element or ion and O representing oxygen. Which of the following could not be a name for this compound?

a)sodium oxide

b)iron(II) oxide

c)copper(I) oxide

d)dinitrogen monoxide

e)water

4.How many moles are in 5.00 lbs of iron(II) phosphate?

a)3.94 molb)5.00 molc)5.72 mold)6.34 mole)15.0 mol

5.How many of the following are examples of a chemical change?

  1. carving wood
  2. snow melting
  3. dry ice (CO2) subliming
  4. burning toast

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

6.A sample of gas in a balloon has an initial temperature of 18°C and a volume of 1340 L. If the temperature changes to 87°C, and there is no overall change of pressure or amount of gas, what is the new volume of the gas?

a)6.03×10–4 Lb)401 Lc)1660 Ld)1080 Le)6480 L

7.How many of the following are true regarding the representation of the mixture below?

I.The mixture contains two different types of molecules.

II.The mixture contains two substances in the gas phase.

III.The mixture contains two different types of compounds.

IV.The mixture contains two pure substances that each contain the same element.

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

8.Which sample contains the greatest percent by mass of nitrogen?

a)1.00 mol Ca(NO3)2

b)2.00 mol Ca(NO3)2

c)3.00 mol Ca(NO3)2

d)All three samples contain the same percent by mass of nitrogen.

e)Cannot be determined without more information given.

9. Which of the following statements isfalse regarding nitrogen and phosphorus?

a)Nitrogen and phosphorus have a relative mass of 14.01 amu to 30.97 amu.

b)N3– and P3– contain a different number of protons, but the same number of electrons.

c)14.01 g of nitrogen and 30.97 g of phosphorus contain the same number of atoms.

d)The odds of picking up one nitrogen atom with a mass of 14.01 amu and one phosphorus atom with a mass of 30.97 amu is 0% (no chance).

e)Nitrogen and phosphorus are both nonmetals.

10.What mass of sodium hydroxide has the same number of oxygen atoms as 100.0 g of ammonium carbonate?

a)1.041 gb)3.122 gc)13.87 gd)41.62 ge)124.9 g

11.Malonic acid is used in the manufacture of barbiturates (sleeping pills). The composition of the acid is 34.6% C, 3.9% H, and 61.5% O. What is malonic acid’s empirical formula?

a)C3H4O4b)CHOc)CH3O3d)C2H3O3e)C3HO

12.Which of the following does not demonstrate Boyle’s law (P1V1 = P2V2 at constant temperature and moles of gas)?

a)Blowing up a balloon so that the balloon inflates to approximately 2 L.

b)A balloon inside a vacuum pump that is turned on, causing the balloon to get bigger.

c)Compressed gas inside a small can is sprayed and emptied completely into a large plastic bag, inflating it.

d)Experiencing some pain on your ear drums while descending in an airplane, causing you to swallow hard so that your ears “pop”.

e)Pushing on the handle of a syringe that is closed on the other end.

13.How many water molecules are in a block of ice containing 3.40 mol of water (H2O)?

a)2.05 × 1024

b)5.65 × 10–24

c)1.77 × 1023

d)4.09 × 1024

e)61.3

14.Consider 5.50 L of a gas at 0.480 atm and 22°C. If the container is compressed to 2.00 L and the temperature is increased to 39°C, what is the new pressure inside the container? Assume no change in the amount of gas inside the cylinder.

a)0.508 atmb)1.25 atmc)1.40 atmd)2.34 atme)2.50 atm

15.A person accidentally swallows a drop of liquid oxygen, O2(l), which has a density of 1.149 g/mL. Assuming the drop has a volume of 0.050 mL, what volume of gas will be produced in the person’s stomach at body temperature (37°C) and a pressure of 1.00 atm?

a)2.0 × 10–6 L

b)0.0055 L

c)0.046 L

d)0.091 L

e)1.5 L

Answer the questions below. Only complete and coherent explanations will receive full credit.Please limit your answers to the space provided.

16.a)The formulas Na2O and N2O look very similar. What is the name for each compound? Why do we use a different naming convention between the two compounds?

b)If you dissolve 5 “units” of Na2O in water, how many particles will be in solution? Include a microscopic sketch of your solution to support your answer.

c)Which compound, Na2O or N2O, has the greatest percent by mass of oxygen? Justify your answer.

17.Consider an elastic balloon filled with 1.00 g of hydrogen gas and 7.94 g of oxygen gas at 25°C.

a)Which gas exerts a greater partial pressure and by what factor? How do you know this? Be sure to show all of your work and to support your answer using the kinetic molecular theory.

b)How does the total pressure inside the balloon compare with the total pressure outside the balloon which is at atmospheric pressure (ignoring the elastic forces of the balloon)? Be sure to support your answer using the kinetic molecular theory.

c)Is the mixture inside the balloon considered a homogeneous or heterogeneous mixture? Thoroughly explain your answer including the use of the kinetic molecular theory.

d)Determine the size of the balloon and the partial pressure of both the hydrogen gas and the oxygen gas. Show all work.