one compound composed of 76.57% Carbon 6.43% Hydrogen and 17.00% Oxygen by mass.
ID: 782832 • Letter: O
Question
one compound composed of 76.57% Carbon 6.43% Hydrogen and 17.00% Oxygen by mass. Please Calculate the empirical formula of the compound of the molar mass of the compound is 94.11g/mol, what is the molecular formula for that compound??
second compound is composed of 53.30% Carbon 11.19% Hydrogen and 35.51% Oxygen by mass.Please Calculate the empirical formula of the compound of the molar mass of the compound is 90.12g/mol, what is the molecular formula for that compound?
15.67 gram sample of a hydrate of magnesium carbonate was carefully heated, without decomposing the carbonate, to drive off the water. The mass was reduced to 7.58 grams. What is the formula of the hydrate??
Anhydrous lithium perchlorate (4.78g) was dissolved in water and recrystallized. Care was taken to isolate all the lithium perchlorate as its hydrate. The mass of the hydrated salt was obtained was 7.21 grams. What hydrate is it??
Please help!!
Explanation / Answer
Consider 100 gms of the compound
There are 76.57 g of C : 76.57 / 12.011 = 6.37
6.43 g of H : 6.43 / 1.00794 = 6.37
17 g of O : 17 / 15.9994 = 1.06
We get
C ( 6.37) H (6.37) O ( 1.06)
now,we divide for the smallest number
C6H6O ==> empirical formula
mass = 94.11 g/mol
Also the molecular formula is C6H6O
53.30 / 12.011 = 4.44 ( C)
11.19 / 1.00794 = 11.1 (H)
35.51 / 15.9994 = 2.22
C2H5O empirical formula
mass = 45.06 g/mol
90.12 / 45.06 = 2
the molecular formula is
C4H10O2
15.67 - 7.58 = 8.09 g of water
8.09 / 18 = 0.45 moles of water
7.58 / 84.3 = 0.0899 moles of MgCO3
0.45 / 0.0899 = 5
the formula is MgCO3 x 5H2O
7.21 - 4.78 = 2.43 g of water
2.43 / 18 = 0.135 moles of water
MM LiClO4 = 106.4 g/mol
4.78 g / 106.4 = 0.0449
0.135 / 0.0499 = 3
The formula is LiClO4 x 3 H2O
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.