Basics and Real World Connections
Define stoichiometry
The relationship between chemical quantities in a balanced equation
what is the formula you use in stoichiometry practice problems for gas laws?
ideal gas law
How can stoichiometry affect rate law?
It affects the value of the rate constant k.
For a neutralization reaction, stoichiometry is used to calculate the ____ ratio of the acids and bases in order for them to neutralize perfectly.
mole
How does stoichiometry relate to thermochemistry?
The enthalpy change of a balanced chemical reaction can be used to construct conversion factors and stoichiometry relate enthalpy change to amounts of substances reacted or produced
In the following chemical equation, N2(g) + 3H2(g) → 2NH3(g), 1 mole of nitrogen reacts with 3 moles of hydrogen to form how many moles of ammonia?
2 moles of ammonia
If 4.000 grams of hydrogen peroxide is placed within a sealed 250 milliliter container at 500 K. What is the pressure of the oxygen gas produced in atmospheres?
9.65atm
One mole of aqueous sulfuric acid (H2SO4) reacts with 2 mol of aqueous sodium bicarbonate in an acid-base reaction. If 0.038 mol sodium hydrogen carbonate reacts in 20 s, calculate the average reaction rate as moles of sulfuric acid consumed per second.
(9.5x10-4 mol/s)
How many moles is 22 g of H2SO4 in the following reaction: H2SO4 + Cl → HCl + HSO4?
0.22 mols
N2(g) + 3 H2(g) → 2 NH3(g) ΔH = −91.8 kJ How much energy is given off when 222.4 g of N2 reacts?
−15.1 kJ
Sn(s) + 2HF(g) → SnF2(s) + H2(g)
How many moles of hydrogen fluoride are required to react completely with 75.0 g of tin?
1.26 mol HF
In the popcorn lab, you had to mass the kernels. What conversion is needed in the ideal gas law? How would you do so?
moles, use stoichiometry to convert grams to moles.
Explain why the rate of disappearance of NO and the rate of formation of N2 are not the same in the reaction, 2CO(g) + 2NO(g) → 2CO2(g) + N2(g).
Because of the 2:1 stoichiometric ratio between NO and N2, the NO must use 2 moles for each mole of N2 produced. This means that the rate of consumption of NO is twice as fast as the rate of production of N2.
Sr(OH)2(aq) + H2O → Sr(aq) + 2OH-(aq)
There is 1L of a 2.0M solution of strontium hydroxide. Find the molarity of 2OH-(aq)
4.0 M OH-
N2(g) + O2(g) → 2 NO(g) ΔH = 180.6 kJ If 558 kJ of energy are supplied, what mass of NO can be made?
15.5 g
How could doctors/pharmacists use stoichiometry?
Stoichiometry can be helpful when calculating the right dosage for patients and it is necessary to use conversion factors
A weather balloon has a volume of 35 L at sea level (1.0 atm). After the balloon is released it rises to where the air pressure is 0.75 atm. What will the new volume of the weather balloon be?
47 L
How does stoichiometry relate to chemical equilibrium?
Stoichiometric coefficients, used to balance a chemical equation, are important because they relate to the equilibrium constants because they are used to calculate them.
find the amount of grams of NaCl produced by 18 g of HCl. HCl + NaOH → H2O + NaCl
29 g NaCl
Given the thermochemical equation: 2 CO2(g) → 2 CO(g) + O2(g) ΔH = 566 kJ How much energy is absorbed when 85.2 g of CO2 are reacted?
548 kJ
Why is stoichiometry necessary in calculations with airbags?
If there were excess or less of the gas produced by the chemical reaction that occurs, the airbag would either be underinflated or overinflated, defeating its purpose.
What volume of carbon dioxide is produced by the combustion of 25.21 g of ethanol (C2H5OH) at 54°C and 728 mmHg? Assume the gas is ideal.
30.6 L
Find Kp - SO2(g)+O2(g)⇌SO3(g) - Partial pressures: SO2- 0.25 atm, O2- 0.45 atm, SO3- 0.3 atm
Kp=3.2
Sodium hydroxide is a strong base. Find the pH of a solution prepared by dissolving 1.0 g of NaOH into enough water to make 1.0 L of solution.
pH = 12.40
For the thermochemical equation Fe2O3(s) + 3 SO3(g) → Fe2(SO4)3 (s) ΔH = −570.2 kJ What mass of SO3 is needed to generate 1,566 kJ?
6.60 × 102 g