how to I figure how much copper is in 2.154 gram of copper sulfide?

gramsCu= 2.154*percentcompositionCu in CuS

= 2.154* (atomicwtCu/(atomicWtCu+atomicWtS)

Copper sulfide is CuS.

The ratio of the atomic weights of Copper and Sulfur is the ratio of the masses of those two elements.

That ratio is 63.5/32.0.

63.5/(63.5+32.0) = 63.5/95.5
= 66.5% of the mass is copper.

To calculate the amount of copper present in a given mass of copper sulfide, you need to consider the chemical formula and molar masses of copper and copper sulfide.

First, let's determine the molar mass of copper sulfide (CuS). Copper has an atomic mass of approximately 63.55 g/mol, and sulfur has an atomic mass of around 32.06 g/mol. Since there is only one copper atom and one sulfur atom in each formula unit of copper sulfide, you can add the atomic masses together to find the molar mass:

Molar mass of CuS = 63.55 g/mol + 32.06 g/mol = 95.61 g/mol

Now that you know the molar mass of copper sulfide, you can calculate the amount of copper in 2.154 grams of copper sulfide using the following formula:

Amount of copper (in moles) = Mass of copper sulfide (in grams) / Molar mass of CuS

Substituting the given values:

Amount of copper = 2.154 g / 95.61 g/mol

Simplifying the equation:

Amount of copper = 0.0225 mol

Finally, to convert the amount of copper from moles to grams, you can multiply the amount of copper (in moles) by the molar mass of copper (63.55 g/mol):

Mass of copper = Amount of copper (in moles) × Molar mass of copper

Mass of copper = 0.0225 mol × 63.55 g/mol

Mass of copper = 1.428375 g

Therefore, there is approximately 1.428 grams of copper in 2.154 grams of copper sulfide.