1, 2, 1
You are calculating the empirical formula of this chemical compound, which is the question with moles, molar mass, and number of moles.
first you divide the mass of carbon by its molar mass(relative formula mass)because there is a formula about moles state: number of moles=mass/molar mass. So, 40/12 is about 3.3. Then, the RFM of H is 1, so the number of mole is 6.7/1=6.7. The RFM of O is 16, whihc means the molar mass od oxygen is 16g, so 53.3/16, which is about 3.3 too.
Next, you get the number of moles in order is; 3.3, 6.7, 3.3. Now we need to look at the ratio between these numbers. 3.3 and 3.3 has a common factor of 1, so the subscript of them are both 1. next use 6.7/3.3, and the greatest common factor is 2, so the answer is 1,2,1.
To solve this kind of questions, there are many steps:
Know what you are calculating about, it's about the empirical formula, so you need to find out the number of moles of each elements.
1) Find the RFM of the element, because that is the molar mass(mass of 1 mole) of this element.
2) number of moles= mass/molar mass. use this formula to help you get the number of moles of each element in this compound
3) look at the relationship between the number of moles of each elements. find out the ratio between them.
4)that 's the answer of this question.
If i got anything wrong, please tell me :)
