Gas Laws
Chemical Reactions & Stoichiometry
Acids, Bases & pH
Thermochemistry & Phase Changes
Equilibrium
100
A way to increase the pressure of a sample gas.
Decrease its volume, increase gas particles, or increase its temperature.
100
Type of reaction for
Pb(NO3)2(aq) + 2NaCl(aq) → 2NaNO3(aq) + PbCl2(s)
Double exchange reaction
100
Adds H⁺ ions to solution
Arrhenius acid
100
The energy required to change a liquid to a gas.
Heat of Vaporization
100
When 1 mol of NO₂ is sealed in a container and allowed to react in the reversible process
2NO2⇌N2O4,
what would you expect to find after some time?
some N₂O₄ and some NO₂
200
A way to increase temperature of a sample of gas.
Decrease volume, add heat at constant volume, or increase pressure in a rigid container.
200
Type of reaction for
Single exchange reaction
200
Calculate the pH of a solution with [H+] = 6.7 × 10–3
pH=−log(6.7×10−3) = 2.174
200
On a heating curve, the flat line at 100°C represents this.
Water evaporating to form a gas
200
A graph shows reactant and product concentrations changing over time in a reversible reaction. At which point is the system at equilibrium?
When the lines for the reactants and products plateau.
300
Meteorologists focus on these two variables because the atmosphere has no container.
Pressure and temperature.
300
Molarity (M) of a 6 L solution that contains 66 g of dissolved KI
1 mole KI = 39.10 + 126.90 = 166.00 g
66g x (1 mole/166g)=0.398 mole/6L = 0.066 M
300
If you dilute an acid or base by a factor of 1000, what happens to the pH?
changes the pH by 3 - up for acid, down for base
300
The equipment used to measure calorie content in food.
Calorimeter
300
How do the values of K for the dissociation of strong acid and a weak acid compare?
The equilibrium constant, K, is higher for a strong acid vs a weak acid.
400
A car tire at 3 atm and 25°C contains how many moles of air if its volume is 8.0 L?
PV=nRT
n=PV/RT
R = 0.082 L.atm/mol.K
n=(3atm ×8.0L)/(0.0821L.atm/mol.K × 298K)
0.98 moles of air
400
Balance the chemical equation:
Cu + HNO3 → Cu(NO3)2 + NO2 + H2O
Cu + 4 HNO3 → Cu(NO3)2 + 2 NO2 + 2 H2O
400
How many grams of MgO can you produce if you start with 37g of O2?
2Mg(s) + O2(g) → 2MgO(s)
Molar mass O₂ = 32 g/mol
37g O2 x (1 mol O2/32g) = 1.16 mol O2
1.16 mol O2 x (2 mol MgO/1 mol O2) = 2.31 mol MgO
Molar mass MgO = 40.3 g/mol
2.31 mol MgO × 40.3 g/mol = 93.1 g MgO
400
How many calories of energy does it take to heat 576mL of water from 1℃ to 30℃?
Specific Heat Capacity of Water = 1 cal/g℃
q=576mL × 1cal/g℃ × 29℃ = 16,704 calories
400
How could you increase the yield of the products using Le Chatelier's Principle?
SO2(g) + NO2(g) ---> SO3(g) + NO(g)
Multiple correct answers.
500
A cylinder with a moveable piston contains 40L of air at pressure of 1 atm at 36°C. If the temperature is kept the same but the pressure inside the cylinder changes to 8 atm, what is the new volume of the container?
Boyle's Law
K=PV = (1 atm)(40L)
K= 40
V = K/P = 40/(8atm) = 5L
500
The LD50 for formaldehyde, CH2O, is 600 mg/kg.
1 mole = 6.02x1023 molecules
1 kg = 2.205lb
1 g = 1000mg
What is the lethal dose for a 175lb person? Answer in grams.
175 lb × (1 kg/2.205 lb) = 79.37 kg
79.37 kg × (600 mg/kg) = 47,622 mg
47,622mg x (1g/1000mg) = 47.6 g (lethal dose)
500
If you have 40 g N2 and 9 g H2 for the reaction shown below, which reactant is a limiting reactant? How many grams of 2NH3 can you produce?
N2(g) + 3H2(g) → 2NH3(g)
Molar mass N₂ = 28 g/mol
40g N₂ x (1 mol N₂/28g) = 1.43 mol N₂
Mole to Mole Ratio
1.43 mol N₂ x (2 mol NH3/1 mol N₂) = 2.86 mol NH3
Convert back to grams
Molar mass NH₃ = 17.0 g/mol
2.86 mol NH3 x (17 g/1 mol NH3) = 48.62g NH3 LR
Molar mass H₂ = 2 g/mol
9.0 g x (1 mol H₂/2g) = 4.50 mol H₂
Mole to Mole Ratio
4.50 mol H₂ x (2 mol NH3/3 mol H2) =3 mol NH3
More than 2.86 mol NH3 when working with N2
500
You place 18g of ice at 0 °C into 400g of liquid water at 25°C in an insulated container. After a while, the ice completely melts. What is the final temperature of the water?
Heat of Fusion of Water = 79.9 cal/g
Specific Heat Capacity of Water = 1 cal/g℃
Energy of melted ice = 18 g×79.9 cal/g = 1438.2 cal
Change in temp of water = 1438.2 cal/(400g x 1 cal/g℃) = 3.6 ℃
Temp of water after ice melted = 25°C - 3.6 ℃ = 21.4°C
Avg. temp of water and ice = (400g)(21.4°C) + (18g)(0°C)/(418g) = 20.48°C
500
In which direction will the equilibrium shift if temperature was increased?
CO2(g) + H2(g) + heat ⇌ CO(g) + H2O(g)
Equilibrium shifts toward the products