What's difference between sigma and pi bond? ?

This image is an example of a(n) a) atom. b) compound. c) mixture. d) molecule.

At 300 mm hg, a gas has a volume of 380 l, what is the volume at standard pressure

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.