vIt is the middle of winter when you go to the store to buy some balloons for a birthday party. After you get to your car with the balloons, you remember you forgot to get a birthday card so you leave the balloons in the car and go back into the store. When you get back to your car the balloons you just bought are now almost flat. Which statement BEST explains what happened?

Explanation:

sorry i do know

The balloons were filled in a warm room with warm air at a certain volume. When they are brought into the car, which was at a much lower temperature, the air inside the balloons cooled down so much that the volume shrunk in the process. This is in accordance to Charles's law where a decrease in the temperature of the gas causes a reduction in its volume.

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

"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"