The solubility is the guide to the maximum amount of solute that can be dissolved in a certain amount of solvent at a certain temperature to make a saturated solution. Any amount less than this would result to unsaturated, while any amount more would result to saturated.
6 g/(50 mL * 1 L/1000 mL) = 120 g/L
Since it is less than the solubility of 125 g/L, then <em>this solution is unsaturated</em>.
Number of moles = mass of product / molecular mass
=mass of product (MgO) / 40.3
Since the mass of MgO is not given in the question, the correct answer choice cannot be given. However, proceeding witht eh above formula will enable you to find the correct number of moles given the mass of MgO.
because it can influence how frequently and sufficiently the particles collide depending on the space it has to do so, for example a large surface area would be have a slower rate of reaction and a lower temperature. (the rate of reaction in terms of concentration, it is diffused from high to low)