A mixture of potassium bromide and potassium hydroxide has a total mass of 5.50 g. If the mixture contains 2.45 g K, what is the mass in grams of potassium hydroxide in the mixture?
KBr molar mass = 39 + 80 = 119 grams which has x moles in the mixture KOH molar mass = 39 + 17 = 56 grams which has y moles in the mixture
119x + 56 y = 5.50 39*x + 39*y = 2.45 that's because
Every mole of KOH and KBr has exactly 1 mole of K in each molecule.
I won't go through the math, but the answer is x = 0.0315 y = 0.0314 The answer to your question involves y*56 from which we get 1.758 grams Sodium Hydroxide
To check we 119x + 56y = 5.50 grams of mixture. 119* 0.0315 = 3.75 grams 56 * 0.0324 = 1.758 Total = 5.51 which is about as close as you can get when rounding.
