Question

What is the mass percentage of carbon in 5.000 G of sucrose

Answer 1

17) 8.4 / 20 x 100

18) 20 . 0.5150

19) 6,50% because (as you said) the law of definite proportions states that regardless of the amount, a compound is always composed of the same elements in the same proportion by mass

Answer 2

Answer : The mass percentage of carbon in sucrose is, 42.1 %

Explanation: Given,

Molar mass of C = 12 g/mole

Molar mass of H = 1 g/mole

Molar mass of O = 16 g/mole

First we have to calculate the molar mass of sucrose.

Molar mass of sucrose
`(C_(12)H_(22)O_(11))` =
`12(12)+22(1)+11(16)=342g/mole`

Now we have to calculate the mass of carbon in 5 g of sucrose.

As we now that there are 12 number of carbon atoms, 22 number of hydrogen atoms and 11 number of oxygen atoms.

The mass of carbon =
`12* 12=144g`

As, 342 g of sucrose contains 144 g of carbon

So, 5 g of sucrose contains
`(5)/(342)* 144=2.105g` of carbon

Now we have to calculate the mass percentage of carbon in sucrose.

Formula used :

`\%\text{ Mass percentage of carbon}=\frac{\text{Mass of carbon}}{\text{Mass of sucrose}}* 100`

Now put all the given values in this formula, we get:

`\%\text{ Mass percentage of carbon}=(2.105)/(5)* 100=42.1\%`

Therefore, the mass percentage of carbon in sucrose is, 42.1 %