What is the frequency of this wave

Determine the number o moles of ions/atoms/particle in the following: 2.50 miles of k2s (let me know how to do)

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

When a spring is compressed, the energy changes from kinetic to potential. which best describes what is causing this change?