Question

How many grams of cu(no3)2 would you need to heat to get 127 grams of copper?

Answer 1

First, you have to figure out how many atoms (or rather moles of atoms) of copper are in 12.7 g of copper. The number of moles is the mass divided by its molar mass. Since copper has a molar mass of 63.456 g/mol, the number of moles =

127 g / 63.456 g/mol = 2.00 mol

Now you know how many atoms of copper you have. The question says that all the copper gets converted to copper (II) oxide, so you just have to figure out how much 0.200 mol of copper (II) oxide weighs. To do this, you need to know that copper (II) oxide = CuO, which has a molar mass of 79.454 g/mol.

Copper (II) = Cu(2+), and Oxide it O(2-), so they form a 1:1 ionic ratio CuO

Molar mass of Cu(2+) = 63.456 g/mol, molar mass of O(2-) = 15.998 g/mol, so molar mass of CuO = 79.454 g/mol

To get the requested mass, you multiply the number of moles of CuO times the molar mass of CuO, giving the following:

2.00 mol * 79.454 g/mol = 159 g of CuO

Credits:Ben Atsma (Quora)

Answer 2

Answer:

375 grams of copper(II) nitrate will give 127 grams of copper on heating.

Explanation:

$Cu(NO_3)_2\rightarrow Cu+2NO_2+O_2$

Moles of copper =$\frac{127 g}{63.5 g/mol}=2 mol$

According to reaction , 1 mol of copper is obtained by heating 1 mol of copper(II) nitrate.

2 moles of copper will be obtained from:

$\frac{1}{1}\times 2 mol=2 mol$ copper (II) nitrate

Mass of the 2 moles of copper(II) nitrate:

$2 mol\times 187.5 g/mol= 375 g$

375 grams of copper(II) nitrate will give 127 grams of copper on heating.