A sample of iodine is easiest to ship as a powder because it is making it easy to break into small pieces. Helium is less .

than the elements that make up the air we breathe, so a balloon filled with helium will float in air.

Plastic is a compound of nonmetallic elements, so its .

properties make it a popular coating for electric wires to prevent the current from escaping.

*ANSWERS

1): brittle.

2): dense.

3) electrically insulating.

I hope this helped your question! (All of these answers are correct by the way :>)

in theory, limestone is composed principally of the compound calcium carbonate - caco3, but in reality this compound is deposited in conditions involving a number of other compounds as impurities so it ends up being a mixture of many compounds.

hope this : -)

tony (lordcaos066)

"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"

level 4 to level 2 : ))

c) should be the answer.