Homework Help

A certain compound contains only C, H, and N. Combustion of 0.125 g of this compound...

user profile pic

lak-86 | Student, Undergraduate | Salutatorian

Posted June 28, 2013 at 5:28 PM via web

dislike 1 like

A certain compound contains only C, H, and N. Combustion of 0.125 g of this compound produces 0.172 g of H2O and 0.279 g of CO2.

Calculate the number of moles of CO2 and H2O.

2 Answers | Add Yours

user profile pic

justaguide | College Teacher | (Level 2) Distinguished Educator

Posted June 28, 2013 at 5:43 PM (Answer #1)

dislike 1 like

The compound contains only carbon C, hydrogen H and nitrogen N. When 0.125 g of the compound undergoes combustion 0.172 g of H2O and 0.279 g of CO2 are produced.

The atomic mass of hydrogen is 1 and that of oxygen is 16. H2O has a molecular mass of 2 + 16 = 18 g/ mole. 0.172 g of water (H2O) is equivalent to 0.172/18 = 9.55*10^-3 moles of H2O

The molecular mass of carbon is 12 and that of oxygen is 16. The molecular mass of CO2 is 12 + 16*2 = 44 g/mole. 0.279 g of CO2 is equivalent to 6.34*10^-3 moles of CO2.

user profile pic

kavya--kammana | Student, Grade 12 | Valedictorian

Posted July 1, 2013 at 10:04 AM (Answer #2)

dislike 1 like

Number of moles = given mass /  molecular mass

No. of moles of H2O= .172 / 18 = .0095556 moles

No. of moles of CO2 =  .279 / 44 = .0063409 moles

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes