Question

Find the empirical and/or molecular formulas

1. Zn = 52%, C = 9.6%, O = 38.4%

2. H = 5.8%, S = 94.2%

3. Sn = 11.775g, O = 3.18g

4. C = 85.7g, H = 14.3g

5. N = 87.5%, H = 12.5%, Mol. Mass = 32 AMU Find the empirical and molecular formulas.

6. P = 0.97g, O = 1.25g, Mol. Mass = 284 AMU Find the empirical and molecular formulas.

7. Bi = 85.65%, O = 6.56%, F = 7.79%, What is the empirical formula?

8. The empirical formula for vitamin C is C3H4O3. If it’s molecular mass is 176g/mole, what is the molecular formula for vitamin C?

Answer 1

Hey @thomaster could you help me out? I think I know how to do it, but would like some clearance!

Answer 2

Or maybe you @satellite73 could help me?

Answer 3

I just need some clarification on how I would go about solving this problem!

Answer 4

@satellite73

Answer 5

So basically it's like this when you are given with the mass of the elements present in the compound
1)Convert the mass of each element to moles using the molar mass
2)Divide each mole value by the smallest number of moles calculated.
Round to the nearest whole number.
So that's ratio is gonna be the ratio of the no. of elements present in the compound.
If u are given with the percentage then you will have to consider that the compound is 100g and consider the mass accordingly !

Answer 6

eg: In you first question it is in percentages nah so you consider 100g of the compound and now take mass of Zn present as 52g, mass of C present as 9.6g and mass of ) present as 38.4 g ! :)

Answer 7

and do the rest of it :)

Answer 8

When you have to find the molecular formula then you need to find the empirical formula first and find the molar mass of the compound given in the empirical formula. If that mass and the given molar masses are equal then the molecular formula = empirical formula.
If the molar masses of the empirical formula and the molecular formula are not equal then you have to divide the molecular formula's molar mass by the molar mass of empirical formula and get the factor. Then multiply the number of each element in the empirical formula and get the molecular formula.