Ethanol has the chemical formula C2 H6 O . A sample of ethanol contains 164grams of C. How many molecules are in the sample? (4.11E24 molecules C2 H6 O)

We have 8.22 1 C atoms

We have 4.11 1 ethanol molecules

Explanation:

Step 1: Data given

Molecular formula of ethanol =

Mass of C = 164 grams

Molar mass C = 12.01 g/mol

Step 2: Calculate moles C

Moles C = mass C / molar mass C

Moles C = 164 grams / 12.01 g/mol

Moles C = 13.66 moles

Step 3: Calculate molecules of C

Atoms C = moles C number of Avogadro

Atoms C = 13.66 moles 6.02 1 molecules/ mol

Atoms C = 8.22 1 C atoms

Step 4: Calculate molecules in the sample

For 1 mol we have 2 moles C

For 13.66 moles C we have 13.66/ 2 = 6.83 moles

Molecules = 6.83 moles 6.02 1 = 4.11 1 molecules.

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.