How can two rocks made by the same process be so different in color

Although the rocks of the produced by similar processes but their chemical composition may vary dependent upon the type of mineral present in these rocks so the color of the rock also varies depending upon the mineral composition.

Explanation:

The rocks are made by basic steps like disintegration of parent rock material, erosion, crystallization, metamorphism, and sedimentation. These basic steps are common in same kind of rocks but their color may vary because of the mineral composition in them for example, Rhyolite is of light colored because of the presence of quartz mineral present in it.

"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"