Asolution containing 80 g of kcl in 200 g of h2o at 50 degrees celcius is cooled to 20 degrees celcius. how many grams of kcl remain in solution at 20 degrees celcius? how many grams of solid kcl crystallized after cooling?

12g KCl will be crystallized

Explanation:

To solve this problem you need to know solubility of KCl in water at 20°C is 34g per 100g of water.

That means the maximum concentration of KCl you can dissolve at 20°C in 200g of water is 34g×2 = 68g of KCl

As solution containing 80g of KCl, the extra KCl will be crystallized after cooling, that is:

80g of KCl - 68g of KCl = 12g KCl will be crystallized

I hope it helps!

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.