How many grams of Cu2S can be formed when 80.0 grams of Cu reacts with 25.0 grams of S?

The tilt of the earth's axis of rotation is responsible for the a) ocean's tides. b) size of the moon. c) brightness of stars. d) earth’s seasons.

Read the chemical equation. 2c2h2 + 5o2 → 4co2 + 2h2o which of the following statements would be correct if one mole of c2h2 was used in this reaction? one mole of oxygen was used in this reaction. five moles of oxygen were used in this reaction. four moles of carbon dioxide were produced from this reaction. two moles of carbon dioxide were produced from this reaction.

Why is the melting of ice a physical change ?