# Chemistry

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.

1. 👍 0
2. 👎 0
3. 👁 60
asked by Laura

## Similar Questions

1. ### 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?

asked by Grace on February 24, 2014
2. ### 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?

asked by nikki on January 25, 2011
3. ### 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

asked by Monique on September 21, 2011
4. ### 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

asked by Anonymous on December 6, 2014
5. ### 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? how much copper must be heated to form 300 grms. of copper

asked by abby on November 13, 2009
6. ### chemistry

Nitrogen gas can be prepared by passing gaseous ammonia over solid copper (II) oxide at high temperature. The other products of the reaction are solid copper and water vapor. If a sample containing 20.3 g of NH3 is reacted with

asked by casey on November 8, 2016
7. ### science

Based on the reactivity series, decide whether the following reaction will occur. If you think there will be no reaction, write down why you think this. If you think a reaction will happen, write down why you think it will happen,

asked by ishaan on June 27, 2011
8. ### Chemistry

copper is a product of the reaction that occurs when dry ammonia is passed over a sample f heated copper(2) oxide.The equation for the reaction is given: 2NH3+3CuO=3Cu+3H2O+N2 Calculate the mass of copper produced if 0.12dm^3 of

asked by Alyssa on November 26, 2014
9. ### 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) +

asked by Jack on September 21, 2010
10. ### chemistry. please help drbob222

One of the reactions involved in the smelting of copper sulfide ores involves copper (I) oxide and copper (I) sulfide: 2Cu2O2 + Cu2S ---> 6Cu + SO2 Assuming that 35.00 g of copper (I) oxide is heated with 25.00 g of copper (I)

asked by Rose on December 7, 2014

More Similar Questions