Limiting Reactants/ Percent Yield
Hydrogen sulfide burns with oxygen to give sulfur dioxide and water.
2H2S(g) +3O2(g) -> 2SO2(g) + 2H2O(g)
How many grams of SO2 are formed from the reaction of 8.52 g of H2S and 9.60 g of O2?
What is 12.8 g of SOs?
A hiker inhales 598 mL of air. If the final volume of air in the lungs is 612 mL at a body temperature of 37 °C, what was the initial temperature of the air in degrees Celsius?
K= 273+C
What is 30.°C?
Boric acid, H3BO3(s), is a weak electrolyte. Would you expect a boric acid solution to contain only ions, only molecules, or mostly molecules and a few ions?
What is mostly molecules and a few ions?
At equilibrium, is the rate of the forward reaction equal or unequal to that of the reverse reaction?
What is equal?
The equilibrium constant, Kc, for the following reaction is 2.0. If the equilibrium mixture contains 2.0 M NO and 1.0 M Br2, what is the molar concentration of NOBr?
2NOBr(g)⇄2NO(g)+Br2(g)
What is 1.4M?
Hydrogen sulfide burns with oxygen to give sulfur dioxide and water.
2H2S(g) +3O2(g) -> 2SO2(g) + 2H2O(g)
How many grams of H2O are formed from the reaction of 15.0 g of H2S and 25.0 g of O2?
What is 7.93 g of H2O?
Isobutane gas, C4H10, is used as a propellant in aerosol spray cans of whipping cream, shaving cream, and suntan spray. What is the pressure, in atmospheres, of 0.125 mole of isobutane in an aerosol can at 21 °C with a volume of 465 mL?
R=0.0821 L/atm
K= 273+C
What is 6.49 atm?
Hydrochloric acid, HCl, is a strong electrolyte. Would you expect a solution of hydrochloric acid to contain only ions, only molecules, or mostly molecules and a few ions?
What is only ions?
Is the following at equilibrium: The rate of the forward reaction is twice as fast as the rate of the reverse reaction.
What is no?
The equilibrium constant, Kc, for this reaction is 54.
H2(g)+I2(g)⇄2HI(g)
If the equilibrium mixture contains 0.015 M I2 and 0.030 M HI, what is the molar concentration of H2?
What is 1.1 x 10-3M?
What is the percent yield of LiHCO3 for the reaction if 8.00 g of CO2 gives 10.5 g of LiHCO3?
LiOH(s) + CO2(g) -> LiHCO3(s)
What is 84.7%?
A balloon containing 8.00 g of oxygen gas has a volume of 5.00 L. What is the volume, in liters, after 4.00 g of oxygen gas is added to the 8.00 g of oxygen in the balloon, if the temperature and pressure do not change?
What is 7.50 L?
How many milliliters of a 6.0 M HCl solution will provide 164 g of HCl?
What is 750 mL of HCl solution?
T/F A concentration is at equilibrium when the concentration of the reverse reaction is the same as the concentration of the forward reaction.
What is false?
Methanol, CH4O, is finding use as a fuel additive. Describe the effect of each of the following changes on the equilibrium mixture for the combustion of methanol:
2CH4O(g)+3O2(g)⇄2CO2(g)+4H2O(g)+1450 kJ
a) adding more CO2
b) adding more O2
a) When the concentration of the product CO2 increases, the equilibrium shifts in the direction of the reactants.
b) When the concentration of the reactant O2 increases, the equilibrium shifts in the direction of the products.
What is the percent yield of LiHCO3 for the reaction if 35.0 g of LiOH gives 76.6 g of LiHCO3?
LiOH(s) + CO2(g) -> LiHCO3(s)
What is 77.1%?
An oxygen gas container has a volume of 20.0 L. How many grams of oxygen are in the container, if the gas has a pressure of 845 mmHg at 22 °C?
R=0.0821 L/atm
K= 273+C
1 atm = 760 mmHg
O2 = 32 g/n
What is 29.4 grams of O2?
How many milliliters of a 0.330 M Na2SO4 solution are needed to react with 26.8 mL of a 0.216 M BaCl2 solution?
Na2SO4(aq)+BaCl2(aq)→BaSO4(s)+2NaCl(aq)
What is 17.5 mL of Na2SO4 solution?
Write the equilibrium expression for the following reaction:
2SO3(g)+CO2(g)⇄CS2(g)+4O2(g)
What is Kc = [CS2][O2]4/[SO3]2[CO2]?
Methanol, CH4O, is finding use as a fuel additive. Describe the effect of each of the following changes on the equilibrium mixture for the combustion of methanol:
2CH4O(g)+3O2(g)⇄2CO2(g)+4H2O(g)+1450 kJ
a) increasing the volume of the container
b) increasing the temperature
c) adding a catalyst
a) When the volume increases, the equilibrium shifts in the direction of the greater number of moles of gas, which is the products.
b) When the temperature is increased for an exothermic reaction, the equilibrium shifts in the direction of the reactants.
c) When a catalyst is added, there is no change in the equilibrium mixture.
Mercury(II) oxide decomposes to mercury and oxygen.
2HgO(s)→2Hg(l)+O2(g) ΔH=+182 kJ
a) Is the reaction exothermic or endothermic?
b) How many kilojoules are needed when 25.0 g of mercury(II) oxide reacts?
a) What is endothermic?
b) What is 10.5kJ?
A gas sample has a volume of 0.256 L with an unknown temperature. The same gas has a volume of 0.198 L when the temperature is 32 °C, with no change in the pressure and amount of gas. What was the initial temperature, in degrees Celsius, of the gas?
K= 273+C
What is 121 °C?
What is the molarity of a BaCl2 solution if 19.4 mL of the BaCl2 solution is needed to react with 15.0 mL of a 0.225 M Na2SO4 solution?
Na2SO4(aq)+BaCl2(aq)→BaSO4(s)+2NaCl(aq)
What is 0.174 M BaCl2 solution?
Write the equilibrium expression for the following reaction:
CH4(g)+H2O(g)⇄3H2(g)+CO(g)
Kc = [H2]3[CO]/[CH4][H2O]
Hydrogen chloride can be made by reacting hydrogen gas and chlorine gas.
H2(g)+Cl2(g)+heat⇄2HCl(g)
For each of the following changes at equilibrium, indicate whether the equilibrium shifts in the direction of the product, the reactants, or does not change:
a) adding more H2(g)
b) increasing the temperature
c) removing some HCl(g)
Equilibrium shifts in the direction of the product for all three parts.