To get the molarity you need to follow this equation
moles of solute
Molarity (M = -----------------------
Liters of solution
But before you apply that equation you need to find the moles of solute and the liters of solution. Follow this equation
Na2SO4 + BaCl2 = BaSO4 + 2 NaCl
Solution
Moles of BaSO4 = 5.28 g
---------------
233.43 g / mol
= 0.0226 moles
Moles of NaSO4 = 0.0226
0.0226 mole
Molarity = -----------------
0.250 L
= 0.0905 mol / L
So the answer is 0.0905 mol / L
Answer: B) The fireworks give off heat
Democritus was the one who had theorized that atoms make up everything and they are indivisible.
Dalton was the creator of the first actual atomic theory, most of his research was on gasses and meteorology.
Thompson was the original man who put together the plum pudding model in which Rutherford later proved wrong during his career.
Rutherford had discovered the nucleus within an atom. He had put together gold foil experiment.
Bohr had developed the idea of neutrons and electrons surrounding the nucleus. He was also the creator of the planetary model we now use to calculate electrons with.