If 3.907 g carbon combines completely with 0.874 g of hydrogen to form a compound, what is the percent composition of this compound?

Question

Olivia Anton · Accepted Answer

#%C=(3.907*g)/(3.907*g+0.874*g)xx100%~=82%# Naturally, in the case of a binary compound, #%H=(100-82)%=??%#

Caleb Adams · Answer

The compound contains #"81.72 % C"# and #"18.28 % H"#.

We are aware #color(white)(mmmmm)"carbon + hydrogen → compound"# #"Mass/g:"color(white)(ml)3.907color(white)(mmm)0.874color(white)(mmmm)4.781# The mass of the compound must be the sum of the masses of #"C"# and #"H"#. #"Mass of compound" = "(3.907 + 0.874) g" = "4.781 g"# The percent by mass formula is #color(blue)(bar(ul(|color(white)(a/a)"% by mass" = "mass of element"/"mass of compound" × 100 %color(white)(a/a)|)))" "# #% "C" = (3.907 color(red)(cancel(color(black)("g"))))/(4.781 color(red)(cancel(color(black)("g")))) xx 100% = 81.72 %# #% "H" = (0.874 color(red)(cancel(color(black)("g"))))/(4.781 color(red)(cancel(color(black)("g")))) xx 100% = 18.28 %# NOTE: You could have gotten the #" % H"# by subtracting the #"% C"# from #"100 %"#. Even though that approach is easier, I like to use the first one. If you make a mistake in calculating #"% C"#, the error carries over into your #"% H"# and makes it wrong. The first method does not depend on the #"% C"#.

Cameron Andrews · Answer

undefined In order to determine the percent composition of the compound, first calculate its total mass by adding the masses of carbon and hydrogen. Next, calculate its percent composition of carbon by dividing its mass by the compound's total mass and multiplying by 100. Finally, calculate its percent composition of hydrogen by dividing its mass by the compound's total mass and multiplying by 100. Percent composition of carbon = (mass of carbon / total mass of compound) * 100 Percent composition of hydrogen = (mass of hydrogen / total mass of compound) * 100 Using the given values as a substitute: Total mass of compound = mass of carbon + mass of hydrogen; Total mass of compound = 3.907 g + 0.874 g = 4.781 g; Percent composition of carbon = (3.907 g / 4.781 g) * 100 ≈ 81.69% Percent