# Chemistry

posted by .

A compound of the element A and oxygen has a mole ratio of A:O=2:3. If 8.0 grams of the oxide contains 2.4 grams of the oxygen,
a. What is the atomic weight of A?
b. What is the weight of one mole of the oxide?
c. What theoretical weight of the oxide is formed when 28 grams of A is heated in excess oxygen? What is the % yield, if 38 grams of the oxide was produced?

• Chemistry -

A2O3 is the compound. If 8.0 g of A2O3 contains 2.4 g oxygen, then mass of A must be 8.0-2.4 = 5.6. If we were trying to determine the formula we would convert grams to moles and find the ratio of the moles to each other. In this case, we already have the mole ratio; we want to determine the molar mass.
moles A = 5.6g/molar mass of x
moles O = 2.4/15 = 0.15
If we want the ratio to be 2:3 and we know O is 0.15 mole, what is the moles A? That must be 0.667*0.15 = 0.1.
Then moles = 5.6/x
0.1 = 5.6/x
x = 56 for the atomic mass.

mass of 1 mole is the molar mass. 2*atomic mass Z + 3*atomic mass O = molar mass.

For c part.
Write and balance the equation between A and O (but you can use Ba for A if you wish).
Convert 28.0 g Ba to moles. moles = grams/molar mass.
Using the coefficients in the balanced equation, convert moles Ba to moles of the oxide.
The g oxide = moles x molar mass. This is the theoretical yield.

Finally, percent yield = (actual yield/theoretical yield)*100 = ?

• Chemistry -

thanks for the help :)

## Respond to this Question

 First Name School Subject Your Answer

## Similar Questions

1. ### A.P Chemistry

Three volatile compounds X,Y, and Z each contain elements Q. The precent by weight of element Q in each compound was determined. Some of the data obtained are given below Percent by weight Molecular Compound of Element Q Weight X 64.8% …
2. ### A.P Chemistry

Three volatile compounds X,Y, and Z each contain elements Q. The precent by weight of element Q in each compound was determined. Some of the data obtained are given below Percent by weight Molecular Compound of Element Q Weight X 64.8% …
3. ### Chemistry

A particular metallic element, M, has a heat capacity of 0.36 J*g*K, and it forms an oxide that contains 2.90 grams of M per gram of oxygen. (a) Using the law of Dulong and Petit (Cp x M = 25 J*mol*K), estimate the molar mass of the …
4. ### Chemistry

A particular metallic element, M, has a heat capacity of 0.36 J*g*K, and it forms an oxide that contains 2.90 grams of M per gram of oxygen. (a) Using the law of Dulong and Petit (Cp x M = 25 J*mol*K), estimate the molar mass of the …
5. ### Chemistry

A certain compound contains carbon, hydrogen , and oxygen. When 1.00 grams of this compound are burned in oxygen gas 1.47 grams of CO2 and 0.600 grams of water are formed. When 2.75 grams of the compound are dissolved in 10.0 grams …
6. ### Chemistry

A certain compound contains carbon, hydrogen , and oxygen. When 1.00 grams of this compound are burned in oxygen gas 1.47 grams of CO2 and 0.600 grams of water are formed. When 2.75 grams of the compound are dissolved in 10.0 grams …
7. ### biology

1 mole of an element or compound contains 6.20 times 10 to the 23rd power atoms or molecules of the element or compound. 1 mole of an element or compound has a mass equal to its mass number (or molecular weight) in grams. For example, …
8. ### A.P. Chemistry

Three volatile compounds X,Y, and Z each contain elements Q. The precent by weight of element Q in each compound was determined. Some of the data obtained are given below Percent by weight Molecular Compound of Element Q Weight X 64.8% …
9. ### CHEMISTRY

In a certain compound of copper and oxygen, a sample weighing 0.5424g contains 0.4831 g of Cu. How many moles of Cu in the sample?
10. ### chemistry

In a certain compound of copper and oxygen, a sample weighing 0.5424g contains 0.4831 g of Cu. How many moles of Cu in the sample?

More Similar Questions