Which of the following formulas has the smallest percent carbon by mass?
CF4
CO2
CH4
C204

CF4

Explanation:

Calculate the molar mass of each compound. Divide the molar mass of Carbon by the molar mass of each compound, then multiply the answer by 100 to get the percentage.

CF4= 12+(19X 4)

=12+76= 88 g/mol

%C= 12/88 x 100= 13.64%

CO2= 12+(16 X 2)

12+32= 44 G/MOL

%C= 12/44 x 100= 27.3%

CH4= 12+ (1 X4)

=12+4

=16 G/MOL

%C= 12/16  X 100= 75%

C204

(12X2) + (16X4)

24+64

= 88 g/mol

%C= 24/88 x 100

= 27.3%