Conversions
How many meters are in 23 km?
23km x 1000m/1km= 23000 or 2.3x10^4m
You can make one sandwich from 2 slices of bread and 1 slice of cheese. You have 10 slices of bread and 3 slices of cheese.
Limiting ingredient: cheese
• Maximum sandwiches: 3
• Bread left over: 10 − 2×3 = 4 slices
H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
Fe2O3
iron(III) oxide
125.67+3.4−12.089
117.1
How many grams are in 12 mg?
12mg x 1g/1000mg= 0.012 or 1.2x10^-2g
One pizza requires 3 cups of flour and 2 cups of cheese. You have 15 cups of flour and 8 cups of cheese.
• Flour allows: 15/3 = 5 pizzas
• Cheese allows: 8/2 = 4 pizzas
• Limiting ingredient: cheese
• Maximum pizzas: 4
• Flour left: 15 - 4×3 = 3 (1 pizza)
N₂ + H₂ → NH₃
N₂ + 3H₂ → 2NH₃
lead(IV) oxide
PbO2
4.56×0.00320
0.0146
How many microliters are in 420. L?
420.L x (1x10^6𝜇𝐿)/ 1L= 4.2x10^8𝜇𝐿
Nitrogen and hydrogen forming ammonia
Reaction: N₂ + 3H₂ → 2NH₃
Given: 1.0 mol N₂ and 2.0 mol H₂.
• Stoichiometry: 1 N₂ : 3 H₂
• N₂ needs H₂: 1.0 × 3 = 3.0 mol H₂ (only 2.0 available)
• Limiting reactant: H₂
• NH₃ produced: 2.0 mol H₂ × (2 mol NH₃ / 3 mol H₂) = 1.33
mol NH₃
• Leftover N₂: 1.0 − 0.667 ≈ 0.33 mol
Fe + O₂ → Fe₂O₃
4Fe + 3O₂ → 2Fe₂O
calcium nitrate
Ca(NO3)2
(45.67-2.3)/6.20
7.00
How many centimeters are in 300. μm?
300. μm x (1m/10^6μm) x (100cm/1m)= 3x10^-2cm
Combustion of propane
Reaction: C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
Given: 0.80 mol C₃H₈ and 3.0 mol O₂.
Stoichiometry: 1 C₃H₈ : 5 O₂
• C₃H₈ needs O₂: 0.80 × 5 = 4.0 mol O₂ (only 3.0 available)
• Limiting reactant: O₂
• CO₂ produced: 3.0 mol O₂ × (3 mol CO₂ / 5 mol O₂) = 1.8
mol CO₂
• Leftover C₃H₈: 0.80 − 0.60 = 0.20 mol
C₂H₆ + O₂ → CO₂ + H₂O
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
ammonium carbonate
(NH4)2CO3
(2.50×10^3)(4.62×10^−2)
1.16×10^2
Children’s Chewable Advil contains 100. mg of ibuprofen per tablet. If the recommended dosage is 10. mg/kg, how many tablets are needed for a 37 lb child? Round your answer to the nearest whole tablet. (1 kg = 2.2046 lb)
37 lb x (1 kg/2.2046 lb) x (10mg/1 kg) x (1 tablet/100mg)= 1.678 tablets= 2 tablets
Neutralization (sulfuric acid and sodium hydroxide)
Reaction: H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O
Given: 0.30 mol H₂SO₄ and 0.40 mol NaOH
Stoichiometry 1 H₂SO₄ : 2 NaOH
• H₂SO₄ would need: 0.30 × 2 = 0.60 mol NaOH
(only 0.40 present)
• Limiting reactant: NaOH
• Na₂SO₄ produced: 0.40 mol NaOH × (1 mol Na₂SO₄ / 2 mol
NaOH) = 0.20 mol Na₂SO₄
• H₂SO₄ used: 0.40 mol NaOH × (1 mol H₂SO₄ / 2 mol
NaOH) = 0.20 mol H₂SO₄
• Leftover H₂SO₄: 0.30 − 0.20 = 0.10 mol
C₄H₁₀ + O₂ → CO₂ + H₂O
2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O
ammonium hypochlorite
NH4ClO
((125.6−17.23)(3.40))/(2.5+0.37)
1.3x10^2