Question

part e
in a lab, strontium (sr) and oxygen (o₂) are combined to produce strontium oxide (sro). after balancing this reaction, determine how many grams of strontium oxide are produced by the complete reaction of 19.6 grams of strontium.
express your answer to the correct number of significant figures.
use the periodic table to get the weights of the elements.
the mass of the sro is

grams.

Explanation:

Step1: Balance the chemical reaction

The balanced reaction is:

$$2\text{Sr} + \text{O}_2 ightarrow 2\text{SrO}$$

This shows 2 moles of Sr produce 2 moles of SrO, so 1:1 mole ratio.

Step2: Find molar mass of Sr

From periodic table, molar mass of $\text{Sr} = 87.62\ \text{g/mol}$

Step3: Calculate moles of Sr

Moles of $\text{Sr} = \frac{\text{mass}}{\text{molar mass}} = \frac{19.6\ \text{g}}{87.62\ \text{g/mol}} \approx 0.2237\ \text{mol}$

Step4: Find moles of SrO

Since mole ratio Sr:SrO = 1:1, moles of $\text{SrO} = 0.2237\ \text{mol}$

Step5: Calculate molar mass of SrO

Molar mass of $\text{SrO} = 87.62\ \text{g/mol} + 16.00\ \text{g/mol} = 103.62\ \text{g/mol}$

Step6: Calculate mass of SrO

Mass of $\text{SrO} = \text{moles} \times \text{molar mass} = 0.2237\ \text{mol} \times 103.62\ \text{g/mol} \approx 23.2\ \text{g}$
(rounded to 3 significant figures, matching 19.6 g)

Answer:

23.2