What differentiates galaxy groups from clusters?

Now consider the reaction when 45.0 g naoh have been added. what amount of naoh is this, and what amount of fecl3 can be consumed by it?

How manyatoms of mercury are in 1.4214e+1 ml sample

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