Help im stuck on this i dont understand

Which best explains why an iceberg floats?

How would the number of moles (n) of o2 change if the atmospheric pressure doubled but all other variables stayed the same

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.