Which element has 21 neutrons and 20 electrons?

An atom of which element reacts with an atom of hydrogen to form a bond with the greatest degree of polarity ?

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.

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?