# Chemistry

posted by .

A 2.612 g sample of a copper oxide, when heated in a stream of H2 gas, yields .592 g H20. What is the formula of the copper oxide?

Again, I need help with this problem. Answer = CuO

Ok nvm.. i got it.

Set up the reaction as best we can surmise at the moment.

CxOy + H2 ---> H2O + Cu

It is not important for this problem to worry about the Cu on the right side. I put it there for completeness. The key point is that all of the oxygen from the oxide ends up in the water. That means the mole quantity of oxygen in the oxide equals the mole quantity of oxygen in the water.

What then is the mole quantity of water?

The mass of water is 0.592 grams. The molar mass of water is approximately 18 g/mol.

0.592 g H2O/18 g/mol = 0.033 mol H2O
(The g units cancel out and the mol unit ends up on top.)

There is one mole of oxygen for every mole of water

0.033 mol H2O Ã— 1 O/H2O = 0.033 mol O.

There is that mole quantity of O in the oxide. It takes of some of the mass of the oxide. What is the mass of 0.033 mol O? The molar mass of O is 16 g/mol.

0.033 mol O Ã— 16 g/mol = 0.53 g O
(The mol units cancel out.)

That mass of oxygen is part of the 2.612 g mass of oxide. Mass of copper in the oxide is the difference between the total mass and the mass of the oxygen.

2.612 g mass of copper oxide - 0.53 g O = 2.08 g copper.

How many moles of copper is that? The molar mass of copper is approximately 63.5 g/mol.

2.08 g Cu/ 63.5 g/mol = 0.033 mol Cu.

CxOy = C(0.033)O(0.033)

However, we like whole numbers. If both subscripts are divide by 0.033 we get

C(1)O(1) or CuO.

## Similar Questions

1. ### chemistry.

A student was asked to make some copper(II) sulfate-5-5 (CuSO4.5(H2O) BY reacting copper(II) oxide (CuO) with sulfuric acid. a) Calculate the molar mass of the copper (II) sulfate-5-water which is (64+32+64) + (10+80)=250 mol b)Calculate …
2. ### chemistry

when heated in the presence of air, 80 grms. of copper completely react to form 100 grms. of copper oxide what is the mass of oxygen that has combined with the copper?
3. ### Chemistry

ammonia gas reacts with copper (ii) oxide at high temperatures to produce elemental nitrogen, copper metal, and water vapor. Assume that 36.2g ammonia reacts with 180.8 g copper ii oxide. (balanced equation: 2 NH4 (ammonium) (g) + …
4. ### chemistry

When copper(II) oxide is heated in the presence of hydrogen gas, elemental copper and water are produced. What mass of copper can be obtained if 22.8 g copper(II) oxide is used?
5. ### Chemistry

A 1.250 g sample of copper wire was heated in air and reacted with oxygen to give 1.565 g of copper oxide product. Calculate the empirical formula of the copper oxide. Please help I'm lost. I need step by step Please and thank you
6. ### Chemistry

calculate the mass percent of sand, sodium chloride and copper(ll) sulfate in a sample that yields: mass of sample= 14.088g, mass of sand=0.2255g, mass of copper(ll)oxide = 0.1994g (assume 100% yield for each of the copper(ll) reactions) …
7. ### Chemistry

Ik this has been answered, but doesn't the copper oxide have something to do with it?
8. ### Chemistry

When copper(II) oxide is heated in the presence of hydrogen gas, elemental copper and water are produced. What mass of copper can be obtained if 34.0 g copper(II) oxide is used?
9. ### chemistry

One of the reactions involved in the smelting of copper sulfide ores involves copper(I) oxide and copper (I) sulfide: 2Cu2O(solid) + Cu2S(solid) ---> 6Cu(solid) + SO2(gas) Assuming that 35.00 g of copper (I) oxide is heated with …
10. ### Chemistry

You synthesized copper (I) chloride and copper (I) oxide. How do they differ from their copper (II) analogs?

More Similar Questions