MIDTERM REVIEWUnit 1 – Diversity of Matter and Chemical BondingUnit 2 – Forms of Matter: Gases

Test Date: Friday, December 13th, 2013

Name: ________________________

Important Topics:

valence shells and valence electrons Lewis dot diagrams structural formulas naming ionic compounds and writing formulas from names naming covalent compounds and writing formulas from names electronegativity bond character continuum VSEPR theory overall polarity of molecules intermolecular forces (London Dispersion, Dipole-Dipole, Ion-

Dipole, Hydrogen Bonding) Celsius and Kelvin temperature scales absolute zero real and ideal gases law of combining volumes Charles’s law Boyle’s law ideal gas law standard temperature and pressure (STP) standard ambient temperature and pressure (SATP)

Practice: Chemical Bonding

1. What is an ionic compound?

2. Show how the following compounds would ‘bond’:a) calcium fluoride

b) magnesium phosphide

c) sodium sulfide

3. Explain how you can predict if a compound is ionic or molecular by looking at its formula.

4. Write the chemical formula for the following compounds:a) mercury (II) sulfide

b) calcium hydroxide

c) chlorine gas

d) sulfur dioxide

e) cesium fluoride

f) ammonium nitrate

g) manganese (IV) oxide

h) lead (IV) sulfite

i) calcium oxalate

5. What is the difference between a polar covalent bond and a non-polar covalent bond? Use examples.

6. What is the difference between an intramolecular bond and an intermolecular bond? Provide an example to illustrate the difference.

7. Explain the three types of intermolecular forces and the criteria for each.

8. How are boiling points determined by IMF? Explain with examples.

9. Complete the following table:

Compound Structural Diagram

VSEPR Shape Molecule Polar or Non-Polar?

Intermolecular Forces

CO2

NI3

BF3

CH4

NH3

H2O

O2 N/A

CH3Cl

CH2F2

Practice: Gas Laws

1. Solve for the missing value in each of the following:

a. P1 = 600mm Hg V1 = 200mL P2 = 780mmHg V2=?

b. P1 = 2.4 atm V1 = 150 mL P2= ? V2= 435mL

2. A sample of air has a volume of 550.0mL at 106oC. At what temperature will its volume be 700.0mL at constant pressure?

3. A sample of gas at 104oC and 0.870 atm occupies a volume of 3.0L. What volume would this gas occupy at 60oC and 1.7 atm?

4. A mixture of three gases A, B and C is at a total pressure of 8.15 atm. The partial pressure of gas A is 2.70 atm; that of gas B is 2.09atm. What is the partial pressure of gas C?

5. a. What is the volume of 1 mole of any gas at STP? __________________

b. What is STP? Provide an answer using at least two different units of pressure and complete sentences.

6. a. How many moles are contained in 2.5L of CO2 at STP?

b. What is the volume in liters of 2.30 mol of N2 at STP?

c. Find the mass in grams of 4.2 L of O2.

6. Use the ideal gas law to calculate the following problems.

a. What is the volume in liters of 2.00 mol of F2 at 100 K and 1.50 atm?

b. Calculate the number of moles of gas contained in 1.0L at 273K and 1.5 atm.

7. Find the molar mass of a gas measured under the conditions specified.

0.250g occupies 1.01L at 31oC and 1.44 atm

Practice Test: Gas Laws

1. Use Boyle’s law to solve for the missing value in each of the following

a. P1 = 600mm Hg V1 = 200mL P2 = 780mmHg V2=?

P1V1=P2V2 (600 mmHg) (200mL) = (V2) 780 mm Hg

(600 mmHg) (200mL)/ 780 mmHg = 154mL

b. P1 = 2.4 atm V1 = 150 mL P2= ? V2= 435mL

P1V1=P2V2 (2.4 atm) (150mL) = P2 (435mL)

(2.4 atm) (150mL) / 435 = 0.83 atm

2. A sample of air has a volume of 550.0mL at 106oC. At what temperature will its volume be 700.0mL at constant pressure? Use Charles’ law to solve this problem.

V1 V2 550mL 700 mL

T1 = T2 379 K = x

T = 482 K or 209oC

3. A sample of gas at 104oC and 0.870 atm occupies a volume of 3.0L. What volume would this gas occupy at 60oC and 1.7 atm?

V2 = 3.0 L X .870 atm 333K

1.7 atm X 377K

V2 = 1.36L

4. A mixture of three gases A, B and C is at a total pressure of 8.15 atm. The partial pressure of gas A is 2.70 atm; that of gas B is 2.09atm. What is the partial pressure of gas C?

A + B + C = 8.15 so …………….. C = (8.15 - 2.7) – 2.09

C = 3.36 atm

5. a. What is the volume of 1 mole of any gas at STP? ____22.4 L______________

b. What is STP? Provide an answer using at least two different units of pressure and complete sentences.

STP stands for standard temperature and pressure. This is the value for the average atmospheric pressure at sea level (1 atm or 760mm of Hg or 101.3 kPa) and the temperature 0oC (273 K) It is under these conditions that 1 mole of a gas will fill 22.4 liters.

6. a. How many moles are contained in 2.5L of CO2 at STP?

X moles = 2.5 L X 1 mole = 0.112 mol

22.4 L

b. What is the volume in liters of 2.30 mol of N2 at STP?

xL = 2.30 mol x 22.4 L = 51.52 L

1mole

c. Find the mass in grams of 4.2 L of O2.—assume STP

x g = 4.2L O2 X 1mol X 32g = 6g

22.4L 1 mole

6. Use the ideal gas law to calculate the following problems. R= 8.314 L . kPa / mol

. K

a. What is the volume in liters of 2.00 mol of F2 at 100 K and 1.50 atm? (PV=nRT)

V =nRT

P V = (2.0 mol) (8.314 L . kPa / mol . K) 100K

151.98 kPa

V = 10.95

b. Calculate the number of moles of gas contained in 1.0L at 273K and 1.5 atm.

n = PV/RT n = (151.98 kPa) (1.0L)

(8.314 L . kPa / mol . K) 273K

n = 0.0669

7. Find the molar mass of a gas measured under the conditions specified. (Molar mass= g/mol)

0.250g occupies 1.01L at 31oC and 1.44 atm (find moles with Ideal gas law)

n = ___(145.908kPa ) ( 1.01L)________ n = .059 molar mass = 0.25g/ .058

( 8.314 L . kPa / mol

. K) ( 304 K) molar mass = 4.3 g/mol