Blackboard chalk contains a certain percentage of calcium carbonate. If a 1.51 g piece of chalk produces 0.665 g of carbon dioxide, what percentage of calcium carbonate is chalk?

The percentage of Calcium carbonate in chalk = 100%

Further explanation

Given

1.51 g piece of chalk produces 0.665 g of carbon dioxide

Required

percentage of calcium carbonate

Solution

Reaction

CaCO3 (s) + 2 HCl (aq) → CaCl2 (aq) + H2O (l) + CO2 (g)

mol CO2 :

= 0.665 g : 44 g/mol

= 0.015

From the equation, mol CaCO3 = mol CO2 = 0.015

mass CaCO3 :

= mol x MW

= 0.015 x 100

= 1.5 g

Mass is the amount of matter in an object.  weight is the measurement of the pull of gravity on an object.  say for example, you travel to the moon which has a different gravitational field compared to the gravitational field of earth. (gravitational fields: earth = 1, moon = 0.165)  now when you are on the moon, the pull of gravity on you is different than on the earth. and as weight is the measurement of the pull of gravity on an object, that means yes, your weight can and will change on the moon.  however, on the moon, on earth or even on jupiter, the amount of mass inside of you remains the same. meaning your physical mass remains constant.  in conclusion it is possible for your weight to change as your mass remains constant.