Answer the following questions in the space provided. 1. Classify each of the following as a homogeneous or heterogeneous substance.
a. iron ore
b. quartz
c. granite
d. energy drink
e. oil-and-vinegar salad dressing
f. salt
g. rainwater
h. nitrogen
2. Classify each of the following as a physical or chemical change.
a. ice melting
b. paper burning
c. metal rusting
d. gas pressure increasing
e. liquid evaporating
f. food digesting
3. Compare a physical change with a chemical change.

iron ore is heter

quartz homo

granite heter

energy drink homo

oil-and vingar salad dressing heter

salt homo

rainwater homo

nitrogen homo

ice melting chemical

burning paper chemical change

the answer would be a

"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"