If 45.8 grams of mgo are dissolved in 205 grams of water, what is the concentration of the solution in percent by mass? 4.48% mgo 18.3% mgo 22.3% mgo 28.8% mgo

percent by mass = mass (MgO) / mass (solution)

mass of solution = 45.8 grams (MgO) + 205 grams (H2O) = 250. grams

mass (MgO) = 45.8 grams

percent by mass = 45.8 grams / 250. grams = 0.1832 = 18.32%

14 days is the half-life of phosphorus-32

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.