4. Barry Um has a sample of a compound which weighs 200 grams and contains
only carbon, hydrogen, oxygen and nitrogen. By analysis, he finds that it
contains 97.56 grams of carbon, 4.878 g of hydrogen, 52.03 g of oxygen and
45.53 g of nitrogen. Find its empirical formula.

Explanation:

1. Build a table with the analysis and the atomic masses

Element      Massgrams    Atomic mass

                        (g)                    g/mol

   C               97.56                 12.011

   H                 4.878                 1.008    

   O                52.03               15.999

   N                45.53               14.007

2. Divide the mass of each element by its atomic mass to obtain the amount of each element in moles

Element      Massgrams    Atomic mass     moles

                        (g)                    g/mol

   C               97.56                 12.011             8.1226

   H                 4.878                 1.008           4.8393

   O                52.03               15.999           3.2521

   N                45.53               14.007           3.2505

3. Divide each amount in moles by the least number of moles: 3.2505

Element       moles          ratio

   C              8.1226         2.5

   H              4.8393         1.5

   O              3.2521          1.0

   N              3.2505         6.0

4. Mutiply each ratio by 2 to obtain whole numbers

Element      ratio    ratio

   C              2.5        5

   H              1.5         3

   O              1.0         2

   N              1.0         2

5. Write the empirical formula

The mole ratios are represented with suberscripts in the chemical formula:

.

sure what is it? ^w^

answer: i would say b.

explanation: