343 W/M2 of energy is emitted by the Sun to the Earth. How much actually reaches the Earth's surface?
O about a third
almost all
about half
about one fourth

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.

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.

Find the number of moles of argon in 364g of argon.