Spilled oil is considered a pollutant. Why is this so? Describe some way of cleaning oil after a spill

You are making a solution of calcium chloride dissolved in water. you add solid, stir, and it dissolves. you add just a spatula tip full, stir, and the solid does not dissolve. how could you describe the solutions before and after adding the spatula tip amount

Ineed ! i have no clue how to do this problem.

To calculate percent by mass, use the equation below: calculate the percent by mass of each element. %n = % %h = % %o = %