A gaseous compound containing carbon and hydrogen was analyzed and found to consist of 83.65% carbon by mass. The molar mass of the compound is 86.2 g/mol. What is the molecular formula of the compound

The molecular formula is C6H14

Explanation:

Step 1: Data given

Suppose the mass of compound = 100 grams

A compound contains:

Carbon = 83.65 % = 83.65 grams

Hydrogen = 16.35 % = 16.35 grams

Atomic mass of carbon = 12.01 g/mol

Atomic mass of hydrogen = 1.01 g/mol

Molar mass of compound = 86.2 g/mol

Step 2: Calculate moles

Moles = mass / molar mass

Moles carbon = 83.65 grams / 12.01 g/mol

Moles carbon = 6.965 moles

Moles hydrogen = 16.35 grams / 1.01 g/mol

Moles hydrogen = 16.19 moles

Step 3: Calculate mol ratio

We divide by the smallest amount of moles

C: 6.965 moles / 6.965 moles = 1

H = 16.19 moles / 6.965 moles = 2.33

This means for 1 mol C we have 2.33 moles H  OR for 3 moles C we have 7 moles H

The empirical formula is C3H7

The molecular mass of this formula is 43.1 g/mol

Step 4: Calculate molecular formula

We have to multiply the empirical formula by n

n = 86.2 g/mol / 43.1 g/mol

n = 2

Molecular formula = 2*(C3H7) = C6H14

The molecular formula is C6H14

a mercury barometer is a device that uses the physical properties of mercury in a tube to measure barometric pressure. mercury barometers are used for : -

1. measurement of atmospheric pressure  

2. determining the altitude of a place

3. weather forecasting

4. calibration and checking of aneroid barometers

5. application in fluid mechanics

6. measurement of pressure in aircrafts

7. surface weather analysis

8. preparation of barographs

9. usage in physical sciences like physics, astronomy & chemistry

10. preparation of aircraft altimeters

characteristics of mercury barometer : -

1.used to define and measure atmospheric pressure.

2.on the average at sea level the column of mercury rises to a height of about 760 mm.

3.this quantity is equal to 1 atmosphere.

4.it is also known as standard atmospheric pressure.

5.a barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.