The solubility of salicilyc acid in water at 20C is .2g in 100mL. The solubility is salicilyc acid in boiling water is 6.67g in 100mL. Calculate the minimum volume of water needed to re-crystallize .550g of crude salicilyc acid.
100 mL x 0.550/6.67 = ?mL
To calculate the minimum volume of water needed to re-crystallize .550g of crude salicylic acid, we need to consider the solubility of salicylic acid in water at both 20°C and boiling water.
First, let's calculate the volume needed to dissolve .550g of salicylic acid at 20°C. Given that the solubility is 0.2g in 100mL, we can set up a proportion:
0.2g / 100mL = 0.550g / x
Cross-multiplying, we get:
0.2g * x = 0.550g * 100mL
x = (0.550g * 100mL) / 0.2g
x = 275mL
This means that at 20°C, a minimum volume of 275mL of water is needed to dissolve .550g of salicylic acid.
Now, let's calculate the volume needed to dissolve .550g of salicylic acid in boiling water. Given that the solubility is 6.67g in 100mL, we can set up another proportion:
6.67g / 100mL = 0.550g / x
Cross-multiplying, we get:
6.67g * x = 0.550g * 100mL
x = (0.550g * 100mL) / 6.67g
x = 8.249mL (approximately)
This means that in boiling water, a minimum volume of 8.249mL (approximately) is needed to dissolve .550g of salicylic acid.
Therefore, the minimum volume of water needed to re-crystallize .550g of crude salicylic acid is 8.249mL.