How many molecules are there in 4dm³ of nitrogen gas

There are 1.078 x 10²³ molecules

Given

4 dm³ = 4 L Nitrogen gas

Required

Number of molecules

Solution

Assumptions on STP (1 atm, 273 K), 1 mol gas = 22.4 L, so for 4 L :

mol = 4 : 22.4

mol = 0.179

1 mol = 6.02 x 10²³ particles(molecules, atoms)

For 0.179 :

= 0.179 x 6.02 x 10²³

= 1.078 x 10²³

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error