Water Class #3 OB: Mastering Table G – the Solubility Curves for 10 Compounds Take it out now please

When you come to my house for chocolate milk and cookies, the cookies will be first rate (oatmeal, lemon, and chocolate chip). Depends on if my wife Janet makes you chocolate milk, or I do, how well that will taste. MINE Janet’s

In reality there is only a certain amount of chocolate that can fit into a glass of milk. I like to find that point and push it. Janet will always leave some extra room for more chocolate (to protect you from getting too excited!). I like to fill that milk up to exactly how much chocolate can fit. That point is called the SATURATION point. A solution is saturated when the solvent (wet part) is holding AS MUCH solute as it can at that temperature. Janet’s chocolate milk is always unsaturated (has room for more chocolate solute!).

In chem, solutions can be saturated or unsaturated. That is, they can hold exactly as much solute in solvent as possible at a temperature, or less solute than is possible. We can see how much of 10 different solutes fits into 100 mL of water, at any temperature, on Table G. Only look at one curve at a time so you don’t get mixed up.

Let’s look at the SO 2 curve first. The state regents board puts all 10 curves on this graph at once to confuse you. Focus on just one at a time and you’ll be fine. First, let’s look at the Y and X axis labels. Y says Solubility In grams of solute (stuff) dissolved into 100 g or 100 mL of water. X is temperature in Centigrade

Let’s look at the SO 2 curve first. How many grams of sulfur dioxide fit into 100 mL of water at 10°C? How about 333 Kelvin? Or, 90°C? About 16 grams, about 6 grams, and then about 4 grams.

How many grams of ammonium chloride fit into 100 mL water at 90°C? How many grams of potassium iodide fit into 100 mL water at 15°? How many grams of ammonia fit into 100 mL of water at 10 °C?

How many grams of ammonium chloride fit into 100 mL water at 90°C? About 72 g NH 4 Cl How many grams of potassium iodide fit into 100 mL water at 15°? About 140 g KI How many grams of ammonia fit into 100 mL of water at 10°C? About 70 g NH 3

TRICKY, tricky, tricky… How many grams of NH 3 fit into 175 mL of water at 10 °C? This graph is standardized to 100 mL of water. We could search for a graph with a 175 mL standard size, but that won’t help when the next solution is a different size again! So what can we do???

TRICKY, tricky, tricky… How many grams of NH 3 fit into 175 mL of water at 10 °C? 10 °C NH 3 H 2 O 70 g 100 mL X g 175 mL Using the standard, we can cross multiply and solve for X, since this is a direct proportion problem. 100 x = x = x = 123 grams (3 SF)

Table G is set at 100 g (really 100 mL) of water. That grams thing is another annoying way the state is playing with your mind! A certain amount of any of these solutes fits into 100 mL of water at any temperature. That will create a way to make a proportion for any size solution. It can be much bigger, or smaller. The proportion is PERFECT. Try this one… How many g of KCl fits into a solution of 22.0 mL at 50°C?

50°C KCl water 42 g 100 mL x g 22.0 mL 100 x = 924 x = 9.24 g KCl (3SF) 9.24 g KCl fits into a little 22.0 mL aqueous solution at 50°C

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Two more, don’t quit… How many grams of KClO 3 solute fits into 844 mL of water at 373 Kelvin?

Two more, don’t quit… How many grams of KClO 3 solute fits into 844 mL of water at 373 Kelvin? 100°C KClO 3 water 60 g 100 mL x g 844 mL 100 x = x = 506 g KClO 3 (3 SF)

How many grams of sodium nitrate will it take to saturate 64.0 mL of water at 283 Kelvin?

10°C NaNO 3 water 80 g 100 mL x g 64.0 mL 100 x = 5120 x = 51.2 g NaNO 3 (3 SF)

Hand in Water HW # 1 now. The Bonding Lab is overdue. The Review Labs #2 + #3 are way late. Check your grades just in case I made a boo boo. No zeros!