- #1

dekoi

1.)(85) A 55-g sample of a geseous fuel mixture contains 0.51 fraction propane C3H8; the remainder is butane. What are masses of propane and butane in sample?

Using the formula: Ax = n(solute)/n(total), i initially solved for total moles. I went about this by multiplying 7 by the molar mass of carbon (there is a total of 7 carbons) and similarly, 18 by the molar mass of hydrogen. This allows me to solve for moles of solute, which i then convert into mass. However, i get an answer of 12.1g and 43.0 g, which differs from the book.

2.) (105) A solution has 0.375 mol Na2CO3, 0.125 mol Ca(NO3)2, and 0.200 mol AgNO3 in 2.0 L of water. Write balanced reactions and calculate molarities of each ion.

I noticed that NO3(-1) is always soluble. CO3(2-) can form solids with Ca+ and Ag+. So i wrote two separate reactions, one in which CaCO3 was the solid, and the other in which Ag2CO3 was the solid. This allowed me to get the moles of Na+, which i then converted into molarity. But I'm not sure this is the correct way of approaching this question.

Thank you.