Compare the type of change that occurs when a substance melts in when a substance that some fire. use complete sentences to justify the type of change that occurs.

Here's what I get  

Explanation:

When a substance melts, that is just a phase change. The substance does not change its chemical make-up. it stays the same. For example, when ice melts, it becomes liquid water. When it freezes again. it is still water, but in a solid form. Melting is a physical change.

When a substance burns, it changes into different substances with different properties. For example, when a match burns, it changes into carbon dioxide and water vapour. Burning is a chemical change.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.