I need help with this question, i dont know the solution to this

Question

how many fewer grams of Li₂CO₃ will dissolve in 225 of water at 60°C than at 20°C

The Solubility of Selected Solids (grams of solute/100 g of water)

Li₂CO₃ - 1.33 (20°C) , 1.01 (60°C)

Answer 1

It's easiest if you look at the solubility as g/ml.

So, at 20ºC the solubility is 1.33 g/100 ml = 0.0133 g/ml

At 60ºC the solubility is 1.01 g/100 ml = 0.0101 g/ml

Now, we can easily convert to grams in 225 ml of water at each temperature:

At 20ºC: 0.0133 g/ml x 225 ml = 2.99 g will dissolve

At 60ºC: 0.0101 g/ml x 225 ml = 2.27 g will dissolve

The difference is 2.99 - 2.27 = 0.72 g

So, 0.72 fewer grams of Li₂CO3 will dissolve at 60º compared to at 20º

Done another way:

20ºC: 1.33 g/100 ml x 225 ml = 2.99 g

60ºC: 1.01g/100 ml x 225 ml = 2.27 g