What might happen to variables in a science experiment that would lead to unusable results?

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.

Measurements that have similar values are: a. usually accurate b. sometimes accurate c. always accurate d. never accurate

I’m an electrically neutral atomic any element, there are equal numbers of