Element a has 15 protons. determine the number of neutrons in its isotope with mass number 33.

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

Compare and contrast physical changes with chemical changes.

Which terms are used to identify pure substances