If you tripled the volume of your sample of chalk what would happen to the mass

The mass will also be tripled.

Explanation:

Density is defined as the mass contained per unit volume.

Density is characteristic of  a substance and it remains constant at a particular temperature.

If volume increases/decreases then mass also increases/decreases proportionally. Hence density remains constant.

Thus when volume of the sample is tripled , the mass will also increase thrice or become tripled.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"