1.in which state of matter do particles move freely ?
2.in what state do particles move closets together ?
3.in what state has an indefinite shape but definite volume ?
4.give an ex of a chemical change of paper
5.whats the difference between chemical and physical change

1. Air

2. solids

3. liquids

4. Paper that burns from fire can't turn back into it's original form.

5. Composition

"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"