PS CHEM: interpreting solubility curves

Decode solubility curves! Practice chemistry concepts like saturation and temperature effects.

Key Terms Info Solute- substance that gets dissolvedSolvent- substance that does the dissolving (i.e. water)Solubility- the maximum amount of solute that will dissolve in a specific amount of solvent at a given temperature (saturated solution).The solubility of a substance is represented by the line (curve) on a solubility graph Examine the solubility graph above. Notice that for most solutions involving liquids and solids, MORE solute can be dissolved at higher temperatures. There are two exceptions to this generalization, but we will only focus on one. NH3is a solute that does not follow this trend. When a substance becomes LESS soluble at higher temperatures, the substance is most likely a gas. The following is an example of how to read the graph. Find the curve for KClO3.At 30°C approximately 10g of KClO3 (as indicated by the dot on the graph) will dissolve. If the temperature is increased to 80°C, approximately 40 grams of the substance (KClO3) will dissolve.(Hint: find the mass of solute that intersects with the line for KClO3 at 80°C). What mass of KNO3 will dissolve at 70ºC? What mass of NH4Cl will dissolve at 90ºC? What mass of NaCl will dissolve at 100ºC? Which solute is most soluble at 15ºC? (aka which one can you put the MOST grams in?) NaNO3 KNO3 NH4Cl Types of Solutions(Hint: Refer back to the KEY TERMS on the first page to guide you!) 1. On a solubility curve, the lines indicate the concentration of a saturated solution - the maximum amount of solutethat will dissolve at that specific temperature.2. Values on the graph (above / below) below a curve represent unsaturated solutions - more solute could be dissolved at that temperature.3. Values on the graph (above / below) above a curve supersaturated solutions – the solvent is holding more than the maximum amount at that temperature. Did You Know!? Because a supersaturated solution contains MOREthanthe maximumamount of solute, if it is disturbed, the solution will actuallyKICK OUT all of the extrasolute!? This is what is being demonstrated in the video.Think of it this way: You are having a party at your house, when some randos show up and now you have more people than you originally invited. What are you going to do? KICK THOSE EXTRA PEOPLE OUT!This is basically what the solution is doing. Types of Solns Solubility Curves Look at the three dots in relation to the NaNO3 curve. Label each dot as representing either a unsaturated, supersaturated, or saturated solution. Sort the following as either being saturated, unsaturated, or supersaturated. Saturated 50g of NH4Cl at 50 ºC Unsaturated 70g of NaNO3 at 30 ºC 70g of KI at 0 ºC Supersaturated 20g of KClO3 at 30 ºC Identifying the Solubility of Solutes at a Given Temperature Match each statement to the correct solubility. KCl at 5 deg C 28 grams KCl at 25 dec C 33 grams KNO3 at 70 deg C 135 grams KI at 15 def C 140 grams NH3 at 90 deg C 10 grams At 90ºC, you dissolved 10 grams of KCl. What statement best describes this solution? saturated unsaturated supersaturated A mass of 120 grams of NaNO3 is dissolved at 30 ºC. Which statement best describes the solution? supersaturated because it is on the line unsaturated because it is below the line unsaturated because it is above the line supersaturated because it is above the line What compound is the most soluble at 20ºC? What compound is the least soluble at 40 ºC?