CHEM 1314 FINAL EXAM REVIEW

Exam 1

100

Tell me about Rutherford's Gold Foil Experiment

Led to the discovery that every atom has a positively charged center (the nucleus)

200

If the walls in a room are 955 square feet in area, and a gallon of paint covers 15 square yards, how many gallons of paint are needed for the room?

7.1 gallons

300

(a) What is the theoretical yield of N2 (in grams) if we start with 1.14 mol CuO? [2NH3 + 3CuO → N2 + 3Cu + 3H2O]. (b) We end up with 6.63 grams of N2. What is the percent yield?

(a) theoretical yield: 10.6 g N2 (b) percent yield: 62.5%

400

Calculate the amount the amount of moles and g that are in 1.2044 x 10^24 Atoms F.

2.0000 moles, 37.997 grams

500

Consider the following reaction: 2 CuCl2 + 4 KI → 2 CuI + 4 KCl + I2. (a) When 0.56 moles of CuCl2 reacts with 0.64 moles of KI, how many moles of I2 are formed? (b) for the reactant in excess, how many moles are left over after the reaction is complete?

(a) 0.16 mol I2 (b) 0.24 mol CuCl2

Exam 2

100

Consider the unbalanced reaction: Al + HBr → AlBr3 + H2 When 3.22 moles of Al reacts with 4.96 moles of HBr, how many grams of H2 are formed?

5.01 grams

200

Calculate the number of mL of 2.00 M HNO3 solution required to react with 216 grams of Ag according to the equation: 3 Ag(s) + 4 HNO3(aq) → 3 AgNO3(aq) + NO(g) + 2 H2O(l) (molar mass of Ag is 107.87 g/mol)

1.33 X 10^3 mL HNO3

300

A gas is heated from 263.0 K to 298.0 K and the volume is increased from 24.0 liters to 35.0 liters by moving a large piston within a cylinder. If the original pressure was 1.00 atm, what would the final pressure be?

0.777 atm

400

A titration was performed based on the following equation: H2C2O4 (aq) + KOH (aq) → K2C2O4 (aq) + H2O (l) In this titration, 44.55 mL of KOH was added to neutralize 15.00 mL of 0.0800 M H2C2O4. What was the concentration (in M) of KOH in the sample?

0.0538 M KOH

500

A tank contains 480.0 grams of oxygen and 80.00 grams of helium at a total pressure of 7.00 atmospheres. Calculate (a) the mole fraction of He and (b) the partial pressure of O2. Must complete both parts to get credit for question

(a) 0.571 (b) 3.00atm

Exam 3

100

A 10 g iron bar (temp = 80C) is dropped into 70 g of water (temp = 25C). What is the final temperature? (specific heat of water is 4.184 J/gC, iron is 0.46 J/gC)

26 C

200

what is the change in enthalpy for this reaction? 2 H2S(g) + 3 O2(g) ---> 2 H2O(l) + 2 SO2(g) 

Standard Enthalpies: 

H2S (g) = -20.63 kJ/mol 

02(g) = 0 kJ/mol

SO2(g) = -296.84 kJ/mol

H20(l) = -285.8 kJ/mol

-1124.02 kJ

300

Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: {{ 2 Al (s) + 3 Cl2 (g) --> 2 AlCl3 (s) }} 2 Al (s) + 6 HCl (aq) --> 2 AlCl3 (aq) + 3 H2 (g)ΔH = -1049. kJ HCl (g) --> HCl (aq)ΔH = -74.8 kJ H2 (g) + Cl2 (g) --> 2 HCl (g)ΔH = -1845. kJ AlCl3 (s) --> AlCl3 (aq)ΔH = -323. kJ

-6387 kJ

400

A balloon of argon gas initially at 2.3 L transfers 485 J of heat to the surroundings. The final volume of the balloon is 2.05 L. The external pressure is 1 atm. What is the total change in energy for the system? (101.3 J = 1 atm*L)

-460 J

500

Consider the following reaction: 2C4H10 + 13O2 → 8CO2 + 10H2O ΔHrxn = -2044 kJ If we have a 10.8 kg sample of C4H10, calculate heat in kJ for the complete combustion of all C4H10 present.

-1.90*10^5 kJ

New Stuff

100

T or F: Charge and size both affect lattice energy, but charge has a greater affect

TRUE

200

Draw the Lewis Structure for the molecule P2. What type of bond do these two atoms share?

Triple covalent bond

300

How many lone pairs of electrons are present in the molecule NO2-

6

400

Identify both the electron geometry and molecular geometry for SO₃^2-

Electron Geometry: Tetrahedral

Molecular Geometry: Trigonal pyramidal 

500

Calculate the percent ionic character of a diatomic molecule with a bond length of 160 pm and a dipole moment of 3.8 D.

50%

Random

100

Complete the reaction and write the net ionic equation. KI (aq) + Pb(NO3)2(aq) -->

Pb2+ (aq) + 2I-(aq) --> PbI2 (s)

200

You have performed a titration on a 30.00 mL sample of HCl. To reach the endpoint of the titration, you added 40.78 mL of 0.130 M NaOH. How many moles of NaOH did you add?

5.30 X 10^-3 moles NaOH

300

Name or write the proper formula for these acids: (a) HNO3 (b) carbonic acid (c) H2S

(a) nitric acid (b) H2CO3 (c) Hydrosulfuric acid

400

The ionization energies for a period 3 element are as follows: 2300 kj (first), 2900 (second), 4000 (third), 6500 (fourth), 31000 (fifth), 40000 (sixth). Which element do these represent?

Silicon

500

The oxygen gas emitted by an aquatic plant is collected over water at a temperature of 293K and a total pressure of 855.2 mmHg. A total of 2.50 L of gas is collected. What mass of oxygen gas is formed? (760 mmHg = 1 atm) (at 293 K, the pressure of water is 17.55 mmHg)

3.67 grams O2