Why has the atomic theory changed so much over the last several centuries?

Why are people not able to scuba dive in the deep part of the ocean

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

How many grams of co(g) are there in 74.5 ml of the gas at 0.933 atm and 30o c?