Which formula represents a nonpolar molecule? ch4hclh2onh3?

The answer for #3 is c but i don't know why

Suppose you have designed a new thermometer called the x thermometer. on the x scale the boiling point of water is 129 ? x and the freezing point of water is 13 ? x. part a at what temperature are the readings on the fahrenheit and x thermometers the same?

Explain what happens at the saturation point when adding salt to water at room temperature.