Question

capasaicin the compount that gives hot taste in chili peppers has the molecular formula of C18H27NO3

a) if the average chili pepper has 50 mg how many moles does it contain?

b) how many molecules are there in this 50 mg sample?

c) how many hydrogen atoms are there in this 50 mg sample?

Answer 1

MM of capsaicin = 18 (12.01) + 3 ( 16.00) + 14.01 + 27 (1.008) = 305.406 g/mol

1. moles = mass ÷ molar mass

           moles = 50 *10³ / 305.406 = 163 moles

2. No. of molecules = ( mass ÷ molar mass) * 6.023 * 10²³

                   = (50 *10³ / 305.406 ) * 6.023 * 10²³   = 981 * 10²³ molecules

3. ( 27 / 305.406 ) *100 = 8.8 % of H

     [( 8.8 * 50 * 10³) / 306.406 ] * 6.023 * 10 ²³= 8.667 * 10²⁵ atoms of H is present