Corrected Hw #3 week two

Homework #9 p 56 and p 82

1.  
1.  The mass of potassium nitrate that will dissolve in 100 g water at the same (60 C) is 105 g.
2.  the mass of potassium nitrate that will dissolve in 100 g of water at 60 degrees C is 45g.
2.  
1.  The amount of potassium nitrate in grams that must be added to form a saturated solution at 30 C is 20 g.
2.  The minimum mass of 30 C water needed to dissolve 25 g potassium

25g/ xg=45gKNO₃/ 100g       xtimes 45g/45= 2500g/45= 56.

3.  
1.  If the solution is agitated 150-95= 55 g of potassium nitrate will precipitate.
2.  150gKNO₃/ x gwater= 95g KNO₃/l00g water = 95x/95= 1500/95 x= 160g-100g= 160g
4. Three teaspoons of sugar will completely dissolve in hot tea because water can become saturated when heated; therefore, more sugar can dissolve when the tea is heated while barely any can dissolve in iced tea.
5. The maximum mass of potassium chloride that will dissolve in 100g of water at 70 C is 48 g.
6.  
1. If the solubility of sugar in water is 2.0 g/mL at room temp, the maximum mass of sugar that will dissolve in 100.0 mL of water is 200g/ mL.
2. The maximum mass of sugar that will dissolve in 355 mL of water 355 as much solvent so 355 x 2g = 710g.
3.  The maximum mass of sugar that will dissolve in 946 mL of water is 946x 2g = 1,892g
7.  
1. At 20 C: NaCl, KCI, KNO₃
2. At 80 C: KNO_{3 ,}NaCl, KCI
8. Saturated means that a substance has reached its full solubility while unsaturated means that the substance has not reached its solubility level and more solute can be added.
9.  
1.  The maximum mass of KNO₃ that can dissolve in 100 g of water at 20 C is 31 g.
2.  At 30 C, 55 g KNO₃ is dissolved in 100 g water. The solution is unsaturated because in 100 g of water KNO₃ can hold 80g when fully saturated.
3.  80g of solid KNO₃ should precipitate as the saturated solution cools from 75 C to 40 C.
10.  
1.  When you add a crystal to an unsaturated solution of KNO₃ the crystal will eventually dissolve.
2.  When you add a crystal to a supersaturated solution of KNO₃ the rest of the solutes will fall out of the solution again forming crystals and sinking to the bottom; it will rebalance its self
3.  When you add a crystal to a saturated solution of KNO₃ the crystal will not dissolve unless heated.
11. 23% concentration of ethanol is dissolved in 115g of water.

 35g of ethanol/ 115+35g of ethanol X 100%= 23 %