Name: _______________________________
Date: ______________
Period: ____
WS Molecular Formulas
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BOX your answers
1. In each of the following, “circle” each empirical formula and “underline” each molecular formula.
(a)
ribose, C5H10O5
(e)
tartaric acid (sour fruit taste), C4H6O6
(b)
acetone, C3H6O
(f)
DEET (insecticide), C12H17ON
(c)
ethanol (alcohol), C2H5OH
(g)
chlorophyll, C55H72MgN4O5
(d)
hydrogen peroxide, H2O2
(h)
ethyl butyrate (pineapple flavoring), C6H12O2
2. The molecular formula of sorbic acid (a food preservative) is C6H8O2.
What is the empirical formula?
3. Determine the molecular formula of a compound with the empirical formula CH2,
and a molar mass of 42 g/mol.
4. A well-known reagent in analytical chemistry, dimethylglyoxime, has the empirical formula
C2H4NO. If its molar mass is 116.1 g/mol, what is the molecular formula of the compound?
5. A compound with an empirical formula of C2H4O and a molar mass of 88 grams per mole.
What is the molecular formula of this compound?
OVER→
6. Rubbing alcohol (isopropyl alcohol) contains 60.0 % C, 13.4 % H, and 26.6% O.
What is the molecular formula of rubbing alcohol if its molar mass is 60.11 g/mol?
(hint: find the empirical formula first)
7. Antifreeze (ethylene glycol) contains 38.72% C, 9.62% H, and 51.60% O by mass.
Its molar mass is 62 g/mol. What is molecular formula of antifreeze?
8. Caffeine contains 49.5% C, 5.15% H, 28.9% N, and 16.5% O by mass.
Its molar mass is 195 g/mol. What is molecular formula of caffeine?
9. A build up of lactic acid is responsible for the soreness you feel when your muscles are fatigued
from exercising. Lactic acid is 40.0% C, 6.67% H, and 53.3% O by mass.
What is the molecular formula for lactic acid if its molar mass is 90.0 g/mol?