# Acetamide has the molecular formula CH3CONH2. Which element makes up the greatest percentage by mass of acetamide?

May 21, 2018

Carbon has the greatest percent by mass at 41%.

#### Explanation:

$C {H}_{3} C O N {H}_{2}$

To find the mass, add all the elements' masses together. Let's make a list to find the mass by element.

Carbon (2 of them) - weighs 12.011g ; 2 of them, so multiply by 2:

$12.011 \cdot 2 = 24.022$g

Hydrogen (5 of them) - weighs 1.008 ; 5 of them, so multiply by 5:

$1.008 \cdot 5 = 5.040$g

Oxygen (1 of them) - weighs 15.999g
Nitrogen (1 of them) - weighs 14.007g

$24.022 + 5.040 + 15.999 + 14.007 = 59.068$
$\frac{24.022}{59.068}$ = 0.40668382204
~0.41, or 41% Carbon