# Chemistry

posted by .

Chromium (II) nitrate forms a hydrate that is 40.50% water by mass. What is its chemical formula?

I just need to figure out how to do it!

• Chemistry -

Cr(NO3)2.xH2O. You want to determine the value of x.

Take a 100 g sample which will give you
40.5 g H2O and
59.5 g Cr(NO3)2

Convert to moles.
40.5/molar mass H2O = ??
59.5/molar mass Cr(NO3)2

Now find the ratio of H2O molecules to 1 molecule Cr(NO3)2.
Check your numbers; this doesn't come out as well as I think it should. Check my work; perhaps I made an error.

## Similar Questions

1. ### Chemistry

A hydrate of zinc nitrate has the formula Zn(NO3)2 . xH2O. If the mass of 1 mol of anhydrous zinc nitrate is 63.67% of the mass of 1 mol of the hydrate, what is the value of x?
2. ### science

I did a hydrate lab in school and these were my results and at the end we have to write the correc formula for the hydrate but I know the answer at the end is supposed to be 5H2O so why do I keep getting 4H2O?
3. ### chemistry

this is for a lab - determining the chemical formula of a hydrate. suppose the hydrate was heated too quickly and some of it was lost of spattered out of the container. explain how hthis would effect a) the calculated percent by mass …
4. ### chemistry

A 2.50 g sample of a hydrate of calcium sulphate losses 0.523 g of water when heated. Determine the mass percent of water in the hydrate and the formula of the hydrate.
5. ### chemistry

A 2.500 gram sample of hydrate of calcium sulfate loses 0.532 grams of water when heated. Determine the mass percent of water in the hydrate and the formula of the hydrate.
6. ### Chemistry

Hi I need with with a prelab calculation for a Hydrate Crystal lab and I am so confused @_@ You don't really need to solve it if you don't want to, I just need an example on how to do these problems 1) Find the mass of the water that …
7. ### chemistry

I need help with this lab. Write the equation for the decomposition of the hydrate, CuSO4*XH2O. Mass of crucible and hydrate: 93.000g Mass of crucible and pure salt: 91.196g I need to calculate the following: 1. mass of water in hydrate …
8. ### Chemistry

I need help with this lab. Write the equation for the decomposition of the hydrate, CuSO4*XH2O. Mass of crucible and hydrate: 93.000g Mass of crucible and pure salt: 91.196g I need to calculate the following: 1. mass of water in hydrate …
9. ### chemistry

Cobalt(2) chloride is commonly obtained from chemical supply houses as a hydrate with the formula COCL2*6H2O an analysis showed that 25.0 g of this hydrate contains 11.3 g of water what is the percent water by weight in this hydrate?
10. ### Chemistry

Predict the effect of each of the following by mass of water in the hydrate and the chemical of the hydrate?

More Similar Questions