Answer:
<em><u>Intermolecular forces determine bulk properties, such as the melting points of solids and the boiling points of liquids. Liquids boil when the molecules have enough thermal energy to overcome the intermolecular attractive forces that hold them together, thereby forming bubbles of vapor within the liquid.</u></em>
Answer:

Explanation:
The hydrocarbon shown has a double bond. Hydrocarbons with double bonds are known as alkenes.
Cyclic alkanes have cyclic structure.
Alkanes only have single bonds.
Alkynes have triple bonds.
So half life is the time taken for a sample to decay to half its original mass, its a constant and applies to any original mass, it could be 5g or 1kg, it will take the same amount of time for the original mass to half. In this case the half life is 3 days.
After 3 days the sample will be at half its original mass, now 50g.
Now we can treat the 50g as if its a new sample. After another 3 days (6 days in total) there will be half of 50g left, = 25g.
Yes, it is true that ions can have a positive or negative charge.