Caffeine, a stimulant found in coffee and soda, has the mass percent composition: c, 49.48%; h, 5.19%; n, 28.85%; o, 16.48%. the molar mass of caffeine is 194.19 g/mol. part a find the molecular formula of caffeine. express your answer as a chemical formula

Assuming 1 mole of caffeine, therefore the mass is 194.19 grams.

C = 0.4948 * 194.19 grams * (1 mol / 12 grams) = 8

H = 0.0519 * 194.19 grams * (1 mol / 1 grams) = 10

N = 0.2885 * 194.19 grams * (1 mol / 14 grams) = 4

O = 0.1648 * 194.19 grams * (1 mol / 16 grams) = 2

So the molecular formula is:

C8H10N4O2

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml