answer with appropriate units

Question

How many grams of copper react to give 1.20 g of Ag?

Cu(s)+2AgNO3(aq)→Cu(NO3)2(aq)+2Ag(s)

Answer 1

Cu(s) + 2AgNO₃(aq) ==>Cu(NO₃)₂(aq) + 2Ag(s) .. balanced equation

We will determine MOLES of Ag equivalent to 1.20 g of Ag, then compute moles of Cu needed. Finally, we will convert moles of Cu to grams of Cu.

moles of Ag in 1.20 g of Ag:

atomic mass Ag = 107.87 g / mole

1.20 g Ag x 1 mol Ag / 107.87 g = 0.011125 mols Ag

moles Cu needed (use stoichiometry of the balanced equation):

0.011125 mols Ag x 1 mol Cu / 2 mols Ag = 0.005562 mols Cu

convert moles Cu to g Cu:

atomic mass Cu = 63.55 g / mol

0.005562 mols Cu x 63.55 g / mol = 0.353 g Cu (3 significant figures)

Answer 2

Cu(s) + 2AgNO3(aq) --------->Cu(NO3)2(aq) + 2Ag(s) .. balanced equation

Steps to solve the problem:

1. Determine the molar masses of the involved substances:

Molar mass of Ag: 107.87 g/mol

Molar mass of Cu: 63.55 g/mol

2. Convert the given mass of Ag to moles:

moles of Ag = 1.2g/107.87 g/mol

moles of Ag = 0.01113 mol

3. Use the stoichiometric coefficients from the balanced equation to find the moles of Cu required: According to the balanced equation, 2 moles of Ag are produced for every 1 mole of Cu reacted.

moles of Cu = molesof Ag/2

moles of Cu = 0.01113/2

moles of Cu = 0.005565 mol

4. Convert the moles of Cu to grams:

grams of Cu = moles of Cu × molar mass of Cu

grams of Cu = 0.005565 × 63.55

grams of Cu = 0.354 grams

To produce 1.20 grams of silver (Ag), 0.354 grams of copper (Cu) react.