Question #c7952

1 Answer
Jul 11, 2017

44.00944.009 "amu"amu

Explanation:

To calculate the mass of one individual molecule of "CO"_2CO2, we need to

  1. Multiply the atomic mass of carbon by however many carbon atoms are in the compound (1)

  2. Multiply the atomic mass of oxygen by however many oxygen atoms are in the compound (2)

  3. Sum the total

1.

If we look at a periodic table, the mass number underneath the carbon symbol should read

color(red)(12.01112.011 color(red)("amu"amu

We multiply this value by the number of "C"C atoms in the compound to find the total mass of carbon in one molecule:

(1)(color(red)(12.011)color(white)(l)color(red)("amu")) = color(red)(12.011(1)(12.011lamu)=12.011 color(red)("amu"amu

2.

We now do the same exact process for oxygen. Its atomic mass is

color(green)(15.99915.999 color(green)("amu"amu

There are 22 atoms of oxygen per molecule of carbon dioxide:

(2)(color(green)(15.999)color(white)(l)color(green)("amu")) = color(green)(31.998(2)(15.999lamu)=31.998 color(green)("amu"amu

3.

The mass of one molecule of "CO"_2CO2 is the sum of the masses of the constituent elements:

"mass CO"_2 = color(red)(12.011mass CO2=12.011 color(red)("amu"amu + color(green)(31.998+31.998 color(green)("amu"amu = color(blue)(44.009=44.009 color(blue)("amu"amu