The Mole & Molar Mass
How many decimal places should be included when writing a molar mass or any mass value?
2 decimal places
When you add up all the percent compositions of elements in a compound, what should the total equal?
100%
In a balanced chemical equation it shows a relationship between the reactants and the products.
Coefficient/Mole Ratio
What is a limiting and excess reactant?
The limiting reactant that is completely consumed and stops the reaction from continuing; The excess reactant that remains after the product is formed.
In dilution problems using the formula M₁V₁ = M₂V₂, what must V₂ represent?
The total volume of the solution after adding more solvent (original solution + added solvent) or Final volume
What is the numerical value of one mole in chemistry?
6.022×1023 particles/molecules/moles
What is the formula for calculating percent composition?
% = (mass of element / mass of compound) × 100
Using the same equation (4 Al + 3 O₂ → 2 Al₂O₃), how many moles of Al₂O₃ are produced when 5.2 moles of Al react?
2.6 mol Al₂O₃
In the reaction 2 Ca + 1 O₂ → 2 CaO, if you start with 5.0 moles of Ca and 3.0 moles of O₂, which is the limiting reactant?
Ca
What is the formula of molarity?
M = moles of solute / liters of solvent
If the average atomic mass of carbon on the periodic table is 12.01 AMU, what is the molar mass of carbon?
12.01 g/mol
Calculate the percent composition of Na in NaCl. (Na = 22.99 g/mol, Cl = 35.45 g/mol, Molar mass = 58.44 g/mol)
39.34%
In the equation 4 Al + 3 O₂ → 2 Al₂O₃, how many moles of O₂ are needed to form 8.8 moles of Al₂O₃?
13.2 mol O₂
What is theoretical yield?
The maximum amount of product that can be made if the reaction worked perfectly
What is the concentration of a solution in which 2.5 moles of KCl is dissolved in 12 liters of water?
0.21 M KCl
What is the molar mass of K₂O? (Use: K = 39.10 g/mol, O = 16.00 g/mol)
94.20 g/mol
In the balanced equation 4 Al + 3 O₂ → 2 Al₂O₃, what is the mole ratio of Al to Al₂O₃?
4:2
In the reaction 2 In + 3 I₂ → 2 InI₃, if the reaction starts with 6.75 moles of I₂, how many moles of InI₃ will be produced?
4.50 mol InI₃
A student performs an experiment expecting to produce 20.0 g of CaCO₃ but only obtains 14.7 g. What is the percent yield?
73.5%
What is the concentration of a solution in which 110 grams of MgCO₃ (molar mass = 84.31 g/mol) is dissolved in 250 milliliters of water?
5.2 M MgCO₃
Convert 150.0 grams of Cd₃P₂ to moles. (Molar mass = 399.17 g/mol)
0.3758 mol
Calculate the percent composition of Mg in MgF₂. (Mg = 24.30 g/mol, F = 19.00 g/mol, Molar mass = 62.30 g/mol)
39.00% Mg
What is the primary purpose of using mole ratios in stoichiometry?
To determine the relationship between reactants and products in a chemical reaction
In the reaction 2 Al(OH)₃ + 3 H₂SO₄ → Al₂(SO₄)₃ + 6 H₂O, if you start with 3.5 moles of Al(OH)₃ and 2.5 moles of H₂SO₄, which is the limiting reactant?
H₂SO₄
A student needs to prepare 250 mL of a 3.0 M solution of sodium chloride. How many grams of sodium chloride are required?
43.83 g