Question

How many grams of oxygen are in 25 grams of sugar?

Answer 1

Answer:

13 grams of Oxygen

Explanation:

Step 1: Find molecular formula of sugar

C₁₂H₂₂O₁₁

Step 2: Convert moles of oxygen present to grams

1 mol O = 16 g O

11 mol O = 176 g O

Step 3: Find molar mass of sugar

C - 12.01 g/mol

H - 1.01 g/mol

O - 16.00 g/mol

12.01(12) + 22(1.01) + 11(16.00) = 342.34 g/mol C₁₂H₂₂O₁₁

Step 4: Set up dimensional analysis

$25 gC_{12}H_{22}O_{11}(\frac{176 gO}{342.34gC_{12}H_{22}O_{11}} )$

Step 5: Multiply/Divide and cancel out units

Grams of C₁₂H₂₂O₁₁ and grams of C₁₂H₂₂O₁₁ cancel out.

We are left with grams Oxygen

25/342.32 = 0.073031(176) = 12.8535 grams Oxygen

Step 6: Simplify

We only have 2 significant figures in this problem. Thus,

12.8535 = 13 g O