What is the meaning of length?

In this chemical reaction, 325 grams of barium (ba) react completely. how many moles of lithium (li) are produced?

Which is a chemical property of iron? a. it forms iron oxide (rust) when exposed to moisture and air. b. it is a gray–black metal that is hard to the touch. c. it has a melting point of 2795°f (1536°c). d. it is a good conductor of heat

May someone me with these science questions