A mystery white powder is made up of 80% C, 8.33% H, and 11.67% N. What is its empirical formula?

Explanation:

We assume there is 100g of this first for simplicity. That means, there will be 80g of C, 8.33g of H, and 11.67g of N. Now, we need to find the moles of each:

C = 80/12.01 = 6.66

H = 8.33/1.008 = 8.26

N = 11.67/14.01 = 0.833

Then, we divide each one by the element with the lowest amount of moles which is N.

We get 6.66/0.833 = about 8 (this is for carbon)

We get 8.26/0.833 = about 10 (this is for hydrogen)

We get 0.833/0.833 = 1 (for Nitrogen)

Then we get the empirical formula

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).