What your question for number 3
A physical property of an element is a property of an element that can observed or measured without changing the chemical nature of the element.
A chemical property of an element is a property of an element that can only be observed or measure when the chemical property of the element is altered or changed.
Based on this;
The boiling point of bromine is a physical property of bromine.
The high reactivity of bromine with many elements is a chemical property of bromine.
Answer:
increase the temperature
Explanation:
The solubility of a gas in a liquid will increase if: Lower the temperature of the solution , and therefore, lower the kinetic energy of the gaseous particles so they can escape the liquid phase less often.