An earthquake is a violent shaking of Earths surface. Where are earthquakes common?

Explanation:

Earthquakes are common in regions within a convergent tectonic plate boundary. This kind of boundary involves collisions between two tectonic plates. Usually the less dense plate (usually the continental) is subducted underneath the more dense (usually the oceanic) plate. This is great friction between the plates due to their rugged nature. Usually, they get stuck and when they suddenly release, the energy is dissipated an earthquake.

"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"