Use the chemical equation to complete the activity. 2Cu+S→Cu2S Copper (Cu) reacts with sulfur (S) to form copper sulfide as shown in the equation. A scientist adds 12.7 grams

Answer 1

To analyze the reaction given by the equation $2\text{Cu}+\text{S}\to {\text{Cu}}_2\text{S}$, we can determine how much reactants (copper and sulfur) are involved and how they relate to the product (copper sulfide) produced.

Given Data

• Mass of copper (Cu) = 12.7 grams

Molar Mass Calculations

1. Calculate the molar mass of copper (Cu):

   • Molar mass of Cu = 63.55 g/mol

2. Calculate the molar mass of sulfur (S):

   • Molar mass of S = 32.07 g/mol

3. Calculate the molar mass of copper sulfide (Cu2S):

   • Molar mass of Cu2S = (2 × 63.55) + 32.07 = 127.10 + 32.07 = 159.17 g/mol

Convert grams of copper to moles

Using the formula: $$\text{moles}=\frac{\text{mass}}{\text{molar mass}}$$

Calculate moles of Cu: $$\text{moles of Cu}=\frac{12.7\text{ g}}{63.55\text{ g/mol}}\approx 0.200\text{ moles Cu}$$

Determine the stoichiometry

The balanced equation shows that:

• 2 moles of Cu react with 1 mole of S to produce 1 mole of Cu2S.

From the balanced equation:

• $2\text{ moles Cu}:1\text{ mole S}:1{\text{ mole Cu}}_2\text{S}$

Determine moles of sulfur needed

To find the moles of sulfur (S) needed for the reaction with 0.200 moles of copper: $$\text{moles of S}=\frac{0.200\text{ moles Cu}}{2}=0.100\text{ moles S}$$

Convert moles of sulfur to grams

Calculate the grams of sulfur needed: $$\text{mass of S}=\text{moles of S}\times \text{molar mass of S}=0.100\text{ moles}\times 32.07\text{ g/mol}\approx 3.21\text{ g}$$

Final Results

The scientist would need:

• 3.21 grams of sulfur (S) to react completely with 12.7 grams of copper (Cu).

This would produce:

• 0.100 moles of Cu2S, which corresponds to approximately 15.87 grams of Cu2S.