Answer:
High temperature increases the number of high energy collisions
Explanation:
Increasing the temperature a reaction takes place at increases the rate of reaction. At higher temperatures, particles can collide more often and with more energy, which makes the reaction take place more quickly.
Answer:
Anything that can be done to increase the frequency of those collisions and/or to give those collisions more energy will increase the rate of dissolving.
Explanation:
depended on the temperature
Answer: The molar mass of each gas
Explanation:
Mole fraction is the ratio of moles of that component to the total moles of solution. Moles of solute is the ratio of given mass to the molar mass.

Suppose if there are three gases A, B and C.
a) 
b) 
c) 
moles of solute =
Thus if mass of each gas is known , we must know the molar mass of each gas to know the moles of each gas.
A polyatomic ion is a group of elements that has a charge that is not 0. for example the charge of P04 is -3
It has to be 120g because each and every chemical equation has to satisfy the law of conservation of mass, ie sum of mass of products is always equal to the sum of masses of reactants. If reactants=120g, then products=120g