The "hardness" of water is usually expressed as parts per million (ppm) by mass of caco3. what is the molar concentration of ca+2 ions in a water sample with a hardness count of 175 ppm?

Aplanet similar to earth has four moons roughly the same distance away. the moon that will most affect tides on the planet is the one that has the greatest a) mass. b) volume. c) density. d) amount of water.