Question

CuSO4 (aq) + Zn(s) →→→ Cu(s) + ZnSO4 (aq)The single-replacement reaction above produces 145.0 g ofan unknown concentration of zinc sulfate. With excess Cusmass of Zn was used?Molar mass of Cu: 63.55 g/molMolar mass of Zn: 65.38 g/molAnswer:g of zinc (Use 4 sig figs)

Answer 1

149.0g of zinc. The mass of zinc used in the single-replacement reaction of copper sulfate and zinc is 149.0 g.

The balanced chemical equation for the single-replacement reaction of copper sulfate and zinc is:

`CuSO_(4(aq)) +Zn_((s)) \to \to \to Cu_((s)) +ZnSO_(4(aq))`

This reaction produces zinc sulfate, but the concentration of the solution is unknown. To determine the mass of zinc used, we can use the following steps:

Calculate the moles of copper produced from the mass of copper produced.

Calculate the moles of zinc used from the moles of copper produced using the stoichiometric ratio of the balanced chemical equation.

Convert the moles of zinc used to grams of zinc using the molar mass of zinc.

Step 1: Calculate the moles of copper produced from the mass of copper produced.

Moles of copper produced = Mass of copper produced / Molar mass of copper

Moles of copper produced = 145.0 g / 63.55 g/mol

Moles of copper produced = 2.281 mol

Step 2: Calculate the moles of zinc used from the moles of copper produced using the stoichiometric ratio of the balanced chemical equation.

The balanced chemical equation tells us that 1 mole of copper sulfate reacts with 1 mole of zinc to produce 1 mole of copper and 1 mole of zinc sulfate. Therefore, the moles of zinc used is equal to the moles of copper produced.

Moles of zinc used = Moles of copper produced

Moles of zinc used = 2.281 mol

Step 3: Convert the moles of zinc used to grams of zinc using the molar mass of zinc.

Grams of zinc used = Moles of zinc used * Molar mass of zinc

Grams of zinc used = 2.281 mol * 65.38 g/mol

Grams of zinc used = 149.0 g

Therefore, 149.0 g of zinc was used in the single-replacement reaction of copper sulfate and zinc.

Answer 2

In this question, we have the following reaction:

CuSO4 + Zn -> Cu + ZnSO4, as the question already says, this is a single replacement reaction

We have:

145.0 grams of Cu (Copper)

We have to find out how much Zn we had at the beginning of the reaction

First thing we need to do is find out how many moles of Copper we have, we will do it by using its molar mass, 63.55g/mol, and the given mass in the question, 145g

63.55g = 1 mol

145g = x moles

x = 2.28 moles of Copper in 145 grams

Now, according to the molar ratio, if we have 1 mol of Zn, we will produce 1 mol of Cu, therefore if we have 2.28 moles of Cu, we will have 2.28 moles of Zinc as well

Now we will find the mass of Zinc, using the number of moles, 2.28 moles and its molar mass, 65.38g/mol

65.38g = 1 mol

x grams = 2.28 moles

x = 149.1 grams of Zinc was used