Molar Mass
The place on the periodic table where molar mass is found.
Where is under the chemical symbol?
How many moles are in 10.0 g of calcium (Ca)?
Find the error: 10.0 g Ca x 40.08 mol/g = 0.25 mol Ca
The unit is g/mol.
If 4 mol of N₂ react, how many moles of NH₃ form?
N₂ + 3H₂ → 2NH₃
Find the error:
4 mol NH3 × 1 mol NH3/1 mol N2 = 8 mol NH₃
The molar ratio should be: 2 mol NH3/1 mol N2
Where to get the numbers for the molar ratios.
2Al + 3Cl₂ → 2AlCl₃
From the coefficients in the balanced chemical equation.
The molar mass of Hydrogen.
What is 1.008 g/mol?
How many moles are in 45 g of water (H₂O)?
Find the error: 45 g x 1 mol/15.999 g = 2.50 mol H₂O
The molar mass should be 18.02 g/mol
2CO + O₂ → 2CO₂
Problem: How many grams of CO₂ form from 28 g CO?
Find the error:
28 g CO × (1 mol CO / 28.01 g CO) x (44.01 g CO₂ / 1 mol CO2) = 44 g CO₂
They didn't use the mole ratio
If 9 mol of H₂ react, how many moles of NH₃ form?
N₂ + 3H₂ → 2NH₃
Find the error:
9 mol H2 × (3 mol H2/2 mol NH3) = 6 mol NH₃
The molar ratio should be 2 mol NH3 / 3 mol H2
The molar ratio of Cl₂ to AlCl₃.
2Al + 3Cl₂ → 2AlCl₃
3 mol Cl2 : 2 mol AlCl3
Find the molar mass of magnesium oxide (MgO)
What is 40.31 g/mol?
How many grams are in 3.5 mol of nitrogen gas (N₂) if the molar mass of N2 is 28.02 g/mol?
3.5 mol × 28.02 g/mol = 98.1 g
CaCO₃ → CaO + CO₂
How many grams of CO₂ form from 100 g CaCO₃?
100 g CaCO₃ × (1 mol CaCO₃ / 100 g CaCO₃) = 1 mol CaCO₃
They didn't use the mole ratio or solve for grams of CO2
If 5 mol of NH₃ form, how many moles of N₂ reacted?
N₂ + 3H₂ → 2NH₃
5 mol NH3 × (1 mol N2/2 NH3) = 2.5 mol N₂
The molar ratio of Al to Cl₂.
2Al + 3Cl₂ → 2AlCl₃
2 mol Al : 3 mol Cl2
DAILY DOUBLE
The molar mass of Volleyballene (C60Sc20).
What is 1619.68 g/mol?
The mass of 0.75 mol of carbon dioxide (CO₂)?
0.75 × 44.01 = 33.0 g
DAILY DOUBLE
Fe₂O₃ + 3CO → 2Fe + 3CO₂
If 160 g of Fe₂O₃ react, how many grams of Fe are produced?
Molar Mass Fe₂O₃ = 159.69 g/mol
Molar Ratio = 1 mol Fe₂O₃ : 2 mol Fe
Molar Mass Fe = 55.85 g/mol
60 g Fe₂O₃ × (1 mol Fe₂O₃ / 159.69 g Fe₂O₃) x (2 mol Fe / 1 mol Fe₂O₃ ) x (55.85 g Fe / 1 mol Fe)
111.7 g Fe
If 12 mol of H₂ react, how many moles of N₂ are required?
N₂ + 3H₂ → 2NH₃
12 mol H2 × (1 mol N₂/3 mol H2) = 4 mol N₂
Interpret the molar ratio of 3Cl₂ : 2AlCl₃.
2Al + 3Cl₂ → 2AlCl₃
3 moles of chlorine gas produce 2 moles of aluminum chloride.
Interpret the molar mass of Hydrogen (1.008 g/mol). Clearly explain what this number means, including how it relates to the number of atoms and the mass of the substance.
How many moles are in 150 g of sodium chloride (NaCl)?
150 ÷ 58.44 = 2.57 mol
2KClO₃ → 2KCl + 3O₂
If 245 g of KClO₃ decompose, how many grams of O₂ form?
molar mass KClO3 = 122.55 g/mol
245 g x (1 mol KClO3 / 122.55 1 mol KClO3) x (3 mol O2 / 2 mol KClO3) x (32.00 g O2 / 1 mol O2)
96 g O₂
1. Balance the chemical equation below
2. Find the number of moles of O2 produced when 8 mole of HgO decompose.
___HgO → ___Hg + ___O2
2HgO → 2Hg + O2
8 mol HgO x 1 mol O2/2 mol HgO = 4 mol O2
Interpret the molar ratio of 2Al : 3Cl₂.
2Al + 3Cl₂ → 2AlCl₃
2 moles of aluminum react with 3 moles of chlorine gas.