How many moles are present in 13.9 grams of Ba(NO3)2?

0.0614 mol
0.0652 mol
0.061 mol

Can someone me with questions 12 and 13 plz.

Which statement best explains the relationship between an area is geography and the temperature of its surface water

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy