Four moles of CO2
a mass of how many grams

= 17.6

Explanation:

Molar mass of CO2 = 44 g mol-1

Mass of 1 mole of CO2 = 44 g

Mass of 0.4 mole = 44 x 0.4

= 17.6g  

the answer is 17.6 that's what I got

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

particle   p is an electron and particle q is a neutron