2013-02-22

Butane in Bunsen Burner in School Laboratory

A common Bunsen burner used in the school laboratory.  It consists of butane gas
The butane gas in the cartridge under combustion in the presence of oxygen gas produce carbon dioxide and water. 

Chemical equation for complete combustion of butane. 
When there is insufficient of oxygen(the hole of Bunsen burner is closed), incomplete combustion occurs and sooty flame is produced. 




2013-02-16

New York Call for a Ban on Styrofoam

What we commonly call  Styrofoam is more technically known as foamed polystyrene.

New York City Mayor Michael Bloomberg recently just plans a ban on Styrofoam food packaging  from stores and restaurants. 










Common uses of Styrofoam

  • disposable coffee cups, plates
  • cushioning material in packaging











The structure of polystyrene. 

2013-02-04

Number of Atoms & Number of Molecules

Which of the following substance contains 1.204 x 1024 atoms?

A  1 mol of nitrogen gas
B  1 mol of ammonia
C  1 mol of water
D  1 mol of argon

Many of my students choose the wrong answer in the current topical test.

1 mol of nitrogen gas consists of 1 x 6.02 x 1023 molecules. 















Number of atoms in 1 mol of nitrogen gas is 2 x 6.02 x 1023 .
(Each nitrogen, N2 molecule consists of 2 nitrogen atoms)

1 mol of ammonia consists of 1 x 6.02 x 1023 molecules











Number of atoms in 1 mol of ammonia gas is 4 x 6.02 x 1023.
(Each ammonia, NH3 molecule consists of 4  atoms) 

1 mol of water consists of 1 x 6.02 x 1023 molecules














Number of atoms in 1 mol of water is 3 x 6.02 x 1023
(Each water, H2O molecule consists of 3 atoms) 

1 mol of argon consistss of 1 x 6.02 x 1023 atoms. 


The correct answer : A