A compound of 2.225 g, known to be a carbohydrate, was analyzed and found to contain 0.890 g of carbon, 0.148 g of hydrogen and the rest was oxygen. How do you determine the percentage composition by mass of the compound?

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Answer 1 · 2017-05-19T14:20:26

#40.0% C#
#6.65% H#
#53.3% O#

The mass percentage of a substance in a compound is represented by the equation

#%compon ent = (g_(compon ent))/(g_(t otal)) xx 100%#

What we can do first is find it how much #O# is present, by subtracting the sum of the masses of #C# and #H# from the total mass:

#g_(O_2) = 2.225g - (0.890g + 0.148g) = 1.187g_(O_2)#

Now, let's use the above formula to calculate the percentage by mass of each component:

#%C = (0.890g)/(2.225g) xx 100% = 40.0%#

#%H = (0.148g)/(2.225g) xx 100% = 6.65%#

#%O = (1.187g)/(2.225g) xx 100% = 53.3%#