Question

unlawful chemistry: the chemical equation below is unbalanced. you will base your analysis upon this unbalanced chemical equation. 2 li + o₂ → 2 li₂o if 27.8 grams of li react with o₂, then determine... - the mass (in grams) of o₂ that reacts, - the mass (in grams) of li₂o produced, - the total mass (in grams) of all reactants, - the total mass (in grams) of all products. 2 li + o₂ → 2 li₂o 27.8 g blank blank blank total reactant mass (g): blank total product mass (g): blank conclusion: these calculations show that mass is not conserved. student name: hayden.c.mcmahon@cloud.redoakisd.org activity: unlawful vs. lawful chemistry progress report 1 2 3 tap to view information: text box check answers recommended: print passage, tables, and graphs

Explanation:

Step1: Balance the chemical equation

First, balance the given unbalanced equation:

$$4\text{Li} + \text{O}_2 ightarrow 2\text{Li}_2\text{O}$$

Molar mass of $\text{Li} = 6.94\ \text{g/mol}$, molar mass of $\text{O}_2 = 32.00\ \text{g/mol}$, molar mass of $\text{Li}_2\text{O} = 2\times6.94 + 16.00 = 29.88\ \text{g/mol}$

Step2: Calculate moles of Li

$$\text{Moles of Li} = \frac{\text{Mass of Li}}{\text{Molar mass of Li}} = \frac{27.8\ \text{g}}{6.94\ \text{g/mol}} \approx 4.006\ \text{mol}$$

Step3: Find moles of $\text{O}_2$ reacting

From balanced equation, 4 mol Li reacts with 1 mol $\text{O}_2$:
$$\text{Moles of O}_2 = \frac{4.006\ \text{mol}}{4} = 1.0015\ \text{mol}$$
$$\text{Mass of O}_2 = 1.0015\ \text{mol} \times 32.00\ \text{g/mol} \approx 32.05\ \text{g}$$

Step4: Find mass of $\text{Li}_2\text{O}$ produced

From balanced equation, 4 mol Li produces 2 mol $\text{Li}_2\text{O}$:
$$\text{Moles of Li}_2\text{O} = \frac{4.006\ \text{mol}}{2} = 2.003\ \text{mol}$$
$$\text{Mass of Li}_2\text{O} = 2.003\ \text{mol} \times 29.88\ \text{g/mol} \approx 59.85\ \text{g}$$

Step5: Calculate total reactant mass

$$\text{Total reactant mass} = 27.8\ \text{g} + 32.05\ \text{g} = 59.85\ \text{g}$$

Step6: Confirm total product mass

Total product mass equals mass of $\text{Li}_2\text{O}$, so it is $59.85\ \text{g}$

Answer:

• Mass of $\text{O}_2$ that reacts: $\approx 32.1\ \text{g}$
• Mass of $\text{Li}_2\text{O}$ produced: $\approx 59.9\ \text{g}$
• Total mass of all reactants: $\approx 59.9\ \text{g}$
• Total mass of all products: $\approx 59.9\ \text{g}$
• Correction to conclusion: These calculations show that mass is conserved.