Download Name__________________________ Honors Chemistry Final

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Honors Chemistry Final Review
Things you need to know for the final
Skills to remember from Semester 1 – writing and balancing equations, writing formulas from words,
predicting products of equations, unit conversions.
Moles
Mole road map
Formula mass
Percent composition
Empirical and molecular formulas
Hydrate formulas
Stoichiometry
Balancing equations and mole to mole ratios
Limiting Reactants
Percent Yield
States of Matter
Kinetic Molecular Theory and its relation to the behavior of gases
Graham’s Law
Gas Pressure
Units of pressure
Daltons law of partial pressure
Phase Changes
Phase Diagrams
Gas Laws
Boyles, Charles, gay lussacs laws
Combined gas law
Ideal gas law
Ideal gas law with density and molar mass
Gas stoichiometry
Solutions
Types of mixtures
Concentration – molarity, molality, % by mass, % by volume, mole fraction
Using molarity as a conversion factor
Factors that affect solvation
Solubility
Henry’s law
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Honors Chemistry Final Review
Boiling point elevation and freezing point depression
Thermo
Specific heat
Heating curve for water
Calculating the heat absorbed by water (Q=mcΔT)
Calorimetry
Heat of combustion
Hess’s law
Heat of formation (products –reactants)
ΔG and ΔS spontaneity
Rates and Equilibrium
Energy Diagrams
Graphing rates of reaction
Collision theory
Factors that affect rate – concentration, temperature, pressure, catalysts, inhibitors
Le Châtelier’s Principle
Writing equilibrium expressions
Calculating Keq and concentrations using a RICE table
Acid/Base Chemistry
3 Models of Acid/Base chemistry
Identifying B-L acids, B-L bases, conjugate acids, and conjugate bases from an acid base reaction.
Amphoterism and Polyprotic acids
Titration calculations
Strong acids/bases vs. weak acids/bases
pH scale and calculating pH, pOH, [H+], [OH-]
Writing Ka/Kb expressions for weak acids/bases
Lab Based Concepts
Collecting gases over water
Hess’s Law and Calorimetry
Acid/Base Titration
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Honors Chemistry Final Review
Practice Problems
Moles Unit
1. Convert 0.27 g of magnesium chloride to moles.
2. Convert 10.0 L of F2 gas (at STP) to grams of F2 gas.
3. What is the number of molecules in 25 g of sodium phosphate?
4. The percent composition of methyl butanoate is 58.8% C, 9.8% H, and 31.4% O. The molar mass of methyl
butanoate is 102 g/mol. What is the molecular formula of methyl butanoate?
5. Calculate the formula mass of Ca(NO3)2
6. What is the mass (in grams) of 3 moles of lead (IV) oxide?
7. What is the number of moles of 50 g of copper (I) phosphate?
8. How many tungsten atoms are in 7.47 g of tungsten metal?
9. What volume do 2.44X1023 molecules of sulfur hexafluoride gas take up?
10. What is the density of 1 mole of sulfur hexafluoride gas at STP?
11. The percent composition of benzene is 92.3% C, 7.7% H. The molar mass of this compound is 78 g/mol. What
is its molecular formula?
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Honors Chemistry Final Review
Stoichiometry Unit
1. How many grams of magnesium metal are required to react with nitrogen gas to form 4.45 g of product?
3 Mg + 2 N2  Mg3N2
2. NH3 decomposes into nitrogen gas and hydrogen gas. Determine the volume of each gas product when 425 g of
ammonia (NH3) decomposes.
3. How many grams of calcium hydroxide are needed to completely neutralize 77 g of nitric acid?
4. How many liters of CO2 are formed when 35.0 g of sodium bicarbonate react with excess HCl (@STP)
Questions 5-6 refer to the following reaction: 2.0 g of potassium chlorate and 1.75 g phosphorus react in the following
way:
potassium chlorate + phosphorus  potassium chloride + diphosphorus pentoxide
5. Determine the limiting reagent. Show your calculation. How many grams of potassium chloride will be made?
6. What is the % yield if 0.20 L of diphosphorus pentoxide gas is produced at STP?
Questions 7-9 refer to the following reaction:
silver nitrate + calcium chloride  silver chloride + calcium nitrate
7. Show the balanced equation.
8. What would be the limiting reagent if you started with 50.0 grams of silver nitrate and 50.0 grams of calcium
chloride?
9. How much of the excess reagent would be remaining from the problem above?
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Honors Chemistry Final Review
States of Matter and Gases Unit
1 . It takes 133 sec for a certain amount of gas x to effuse. It takes 22 sec for the same number of moles of N 2 to
effuse. Find molar mass of gas x.
2. A mixture of 40.4 g of ne gas and an 22 g of CO2 gas is in a container at a total pressure of 90 kPa.
a. Find the mole fraction of each gas. b. Find the partial pressure of each gas
3. Xe gas effuses from a certain container at a slow rate. An unknown gas effuses from the same container at a
rate 3x faster than the Xe gas. What is the molar mass of the unknown gas?
4. A 110 g sample of C3H8 gas has a partial pressure of 500 kPa in a mixture with 5.6 g of N 2 gas. What is the total
pressure of the mixture?
5. What is the new volume of a gas if its initial pressure is 650 mmHg, its initial volume is 380 cm 3, and you change
the pressure to 520 mmHg?
6. At constant pressure, a balloon containing 0.5 L of an unknown gas at 28 oC is placed in a refrigerator and
allowed to cool to 4 oC. What is its new volume?
7. On a cold 12 oC, low 0.85 atm pressure summer day a certain N 2O filled balloon has a volume of 4.5 L. What is
the mass of the gas in the balloon?
8. Water and methane (CH4) can react to produce hydrogen gas and carbon dioxide gas. When 0.065 g of methane
reacts with excess water, the gaseous products are collected by displacing water in an inverted tube at a pressure
of 780 mmHg. The temperature of the water is 17oC. Write the balanced chemical equation.
Calculate the pressure of gas collected in the tube. Calculate the volume of gas in the tube.
9 . In an alternate universe, you react 3.0 g of aluminum with excess HCl and collect 550 mL of H 2 gas over water.
The pressure and temperature of your experiment were 800 mmHg and 300K. What is the value of R in this
universe?
10. What is the molecular weight of a gas that has a density of 3.02 g/L at 80 oC, 1.4 atm?
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Honors Chemistry Final Review
Solutions Review Problem Set
1. How much of a 12M H3PO4(aq) stock solution do I need to prepare 2.3 liters of a 2M H3PO4(aq)
solution)?
2. What is the freezing point of a solution containing 95g of aluminum nitrate in 500 mL of water?
3. How many grams of glucose (C6H12O6) are in 500 mL of a 3% by mass solution?
4. How many grams of potassium hydroxide would I need to make 750 mL of 0.25M aqueous solution?
5. What is the solubility in alcohol of gas X at 345 mmHg if at 0.85atm it has a solubility of 1.88 g/liter?
6. What is the ionic factor of a solute if a 2.8 m aqueous solution had a freezing point of -15.6 oC? Give
one possible example of what the solute could be?
7. How many grams of Ca(OH)2 are needed to make 100.0 mL of 0.250 M solution?
8. How many moles of Na2CO3 are there in 10.0 L of 2.0 M solution?
9. If I add 25 mL of water to 125 mL of a 0.15 M NaOH solution, what will the molarity of the diluted
solution be?
10. How much 0.05 M HCl solution can be made by diluting 250 mL of 10 M HCl?
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Honors Chemistry Final Review
Thermo Unit
1. How many joules of heat are needed to change 50.0 g of liquid water at 15 oC to gaseous water at 120.0 oC?
Remember that the water will go through a phase change.
2. 83.8 g of a certain metal is heated to 600 oC. The metal is then dropped into a calorimeter containing 75.0 g of
water at 30 oC. The temperature of the water rises to 50 oC. What is the specific heat of the metal?
3. Zinc has a specific heat capacity of 0.39 J/goC. When 300 J of heat is absorbed by a sample of zinc, the
temperature rises from 25oC to 200oC. What was the mass of the zinc sample?
4. Using the standard enthalpies of formation,
H of :
CO(g)
= -110.5 kJ/mol
CO(NH2)2(s)
= -333.19 kJ/mol
NH3(g)
= -46.19 kJ/mol
Calculate the standard enthalpy of reaction for:
CO(NH2)2(s) + H2(g)  2 NH3(g) + CO(g)
5. Balance this equation,
CO(g) + Fe2O3  Fe(s) + CO2
ΔHr = +24.7 kilojoules/mol.
How much heat in kilojoules is released when 560 grams of CO reacts?
6. You have a sample of ice with a mass of 36 g at a temperature of –25 oC. How many kilojoules of heat are
required to heat the ice all the way to 125 oC? Remember that the ice will go through 2 phase changes!
7. Given these reactions: C + O2  CO2
ΔHr = -393.5 kJ
2CO  CO2 +C ΔHr = -172.5 kJ
What would be the ΔHr value for the reaction: 2CO+ O2  2CO2 ?
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Honors Chemistry Final Review
Rates and Equilibrium Unit
Draw an energy diagram for the exothermic reaction, 2KClO3  3O2 + 2KCl
Label products, reactants, and activation energy.
Is heat a reactant or a product?
On the graph above, illustrate how the reaction profile would change if a catalyst is added to the reaction.
Consider the balanced chemical equation, 2KClO3  3O2 + 2KCl
If you initially have 16 M of 2KClO3, 0.5M O2, and no KCl, and you measure the formation rate of O 2 to be 0.6 M/s,
graph the concentration vs. time graph for the reaction.
Le Châtleier’s Principle
NaOH(s)
Na+(aq) + OH-(aq) + 10.6 kcal (of heat)
(Remember that pure solids and liquids do not affect equilibrium values)
Stress
Equilibrium shift
Add NaOH (s) ____________________________________
Add NaCl (Adds Na+)_______________________________
Add KOH (Adds OH-)_______________________________
Add H+ (Removes OH-)_____________________________
Increase temperature______________________________
Increase pressure_________________________________
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Honors Chemistry Final Review
N2 (g) + 3H2(g)
2NH3 (g) + 22 kcal (of heat)
Stress
Equilibrium shift
Add N2
____________________________________
Add H2
____________________________________
Add NH3
____________________________________
Remove N2 ____________________________________
Remove H2
__________________________________
Remove NH3 ___________________________________
Decrease temperature______________________________
Increase pressure_________________________________
Dinitrogen dioxide decomposes into nitrogen monoxide.
a. Write the balanced chemical equation for the reversible reaction.
b. Write the Keq expression.
Consider the reaction (again) 2KClO3
3O2 + 2KCl. Initially you have 16 M KClO3, 0.5M O2, and 0 M KCl. At
equilibrium you measure 8.5 M O2. What is Keq?
Consider the reaction N2 + 3H2
2NH3. At the start of the reaction [N2] = 4.3 M. At equilibrium [N2] = 1.57 M,
[H2] = 2.5 M, and [NH3] = 8.25 M. What is Keq?
For the reaction 2A (g) + 4B(g)
3C (g) + 2D (g) initially, [B] = 8.35 M, and at equilibrium, [B] = 4.61 M, [C] = 0.56 M,
[D] = 1.02 M. If the Keq = 3.2x10-3 M, what are the initial concentrations for A, C, and D?
Given the reaction, N2O4 (g)
2NO2, the initial [N2O4] = 8.5 M, and at equilibrium [N2O4] = 3.4 M. Find the initial
concentration of NO2 if the Keq = 85.
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Honors Chemistry Final Review
Acids and Bases Unit
Label the B-L acid (A), base (B), conjugate acid (CA), and conjugate base (CB) in each of the following reactions.
1. H2SO4(aq) + NH3(aq)  HSO4-(aq) + NH4+(aq)
2. HC2H3O2(aq) + H2O(l)  H3O+(aq) + C2H3O2-(aq)
3. NaHCO3(aq) + HCl(aq)  NaCl(aq) + H2CO3(aq)
4. HPO4-2(aq) + H2O(l)  H2PO4-(aq) + OH-(aq)
5. If it takes 50 mL of 0.5 M KOH solution to completely neutralize 125 mL of sulfuric acid solution (H 2SO4), what is
the concentration of sulfuric acid?
6. It requires 54 mL of 0.1 M NaOH to neutralize 125 mL of an HCl solution, what is the concentration of HCl?
7. A titration is performed with 285 mL HNO3 and LiOH. To neutralize the acid, the student must add 12.5 mL of 0.3
M LiOH. What is the concentration of HNO3.
8. Complete the table below for these four solutions
[H+]
[OH-]
-6
3.6 x 10
2.7 x 10-2
pH
pOH
9.34
13.68
9. If 2.5 moles of HCl were dissolved in 42 L of water, what would the pH be? pOH?
10. The strong base, NaOH, was dissolved in water. If 4.2 moles of NaOH was dissolved in 245 L of water, what is
the pOH of the solution? What is the pH?
11. If the hydroxide ion concentration of a certain solution was 2.6x10-4 M, what is the pH? What is the [OH-] ?
12. The pH of a certain solution was 1.45. What was the pOH? What was the [OH -] ?
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Honors Chemistry Final Review
13. Write the ionization equations and Ka expressions for the following weak acids:
a. HNO2
b. HF
c. HCN
14. For each weak acid above, calculate the pH for:
a. 1.5 M solution of CH3COOH if Ka = 1.8 x 10-5
b. 0.12 M solution of HF if Ka = 6.3 x 10-4
c. 0.5 M solution of HNO2 if Ka = 6.2 x 10-10