All of these tools are used for science but which tool is used specifically for earth science

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

In which reaction is precipitation occurring?

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.