MOLES
How many molecules of CO₂ are in 0.250 mol CO₂?
1.505 × 10²³ molecules
Find the molar mass of Al₂(SO₄)₃
342.16 g/mol
Balance:
__ Fe + __ O₂ → __ Fe₂O₃
4Fe + 3O₂ → 2Fe₂O₃
N₂ + 3H₂ → 2NH₃
How many moles NH₃ form from 4.0 mol H₂?
2.7 mol NH₃
2H₂ + O₂ → 2H₂O
If 5 mol H₂ reacts with 2 mol O₂, identify the limiting reactant
O₂
How many grams of N₂ are in 31.75 mol N₂?
889.4g of N₂
A compound contains:
40.0% C
6.70% H
53.3% O
Find the empirical formula
CH₂O
Balance:
__ C₂H₆ + __ O₂ → __ CO₂ + __ H₂O
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
2Mg + O₂ → 2MgO
How many grams MgO form from 6.0 mol Mg?
2.4 x 10^2 g MgO
N₂ + 3H₂ → 2NH₃
If 6 mol N₂ react with 12 mol H₂, which reactant is limiting?
H₂
How many liters of NH₃ at STP are in 3.25 × 10²³ molecules NH₃?
12.1 L
Empirical formula = CH₂O
Molar mass = 90 g/mol
Find the molecular formula
C₃H₆O₃
Predict the products, determine reaction type, and balance:
Na₂CO₃ + Ca(NO₃)₂ →
Na₂CO₃ + Ca(NO₃)₂ → CaCO₃ + 2NaNO₃
(Double replacement)
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
How many moles CO₂ form from 3.0 mol propane?
9.0 mol CO₂
2Al + 3Cl₂ → 2AlCl₃
If 10.0 mol Al reacts with 12 mol Cl₂, how many moles AlCl₃ form?
8.0 mol AlCl₃
How many grams of CO₂ are present in 4.48 L CO₂ at STP?
8.80 g
A compound contains:
27.3% C
72.7% O
Find the empirical formula
CO₂
Predict the products, determine type of reaction, and balance:
Al + CuCl₂ →
2Al + 3CuCl₂ → 2AlCl₃ + 3Cu
Single replacement
Fe₂O₃ + 3CO → 2Fe + 3CO₂
How many grams Fe form from 120.0 g Fe₂O₃?
83.86 g Fe
2Al + 3Cl₂ → 2AlCl₃
If 10 mol Al reacts with 12.2 mol Cl₂, how many moles of excess reactant remain?
1.87 mol Al
How many atoms of oxygen are in 2.50 mol CaCO₃?
4.52 × 10²⁴ O atoms
A compound contains:
54.5% C
9.1% H
36.4% O
Molar mass = 88 g/mol
Find the molecular formula
C₄H₈O₂
Predict the products, determine the reaction type, and balance:
Pb(NO₃)₂ + KI →
Hint: is Pb a transition metal?
Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
Double replacement
2Al + 3Cl₂ → 2AlCl₃
How many grams AlCl₃ form from 15.0 g Al?
74.1 g AlCl₃
CaCO₃ → CaO + CO₂
A student heats 50.0 g CaCO₃ and actually collects 25.0 g CaO.
What is the percent yield?
89.3%