What percentage of the total mass of khco₃ is made up by nonmetallic elements?
a. 17%
b. 83%
c. 61%
d. 20%
e. 50%

Mass of K = 39.1g/mole
Mass of H = 1g/mole
Mass of C = 12g/mole
Mass of O = 16g/mole
Mass of KHCO3 = 39.1 + 1 + 12 + 3*16 = 100,1g/mole

100% 100.1g of KHCO3
x% 12g of C
x = 11,99% of C in KHCO3

100% 100.1 of KHCO3
y% 3*16g of O
y = 47,95% of O in KHCO3

100% 100.1g of KHCO3
z% 1g of H
z = 0,99% of H in KHCO3

11,99% + 47,95% + 0,99% = 60,93% ≈ 61%

C

Depends on the speed of the car.