Unit 10: Solutions an Introduction

Solution= Solvent + Solute Solvent= the dissolving agent Solute= what is dissolved Solution= what is made when the 2 are combined Remember: All solutions are HOMOGENEOUS!!!!

3 Types of Solutions: Unsaturated solution- solutions containing a lower concentration of solute than is possible. (more can be added) Saturated solution- a solution in which the solvent has dissolved as much solute as it can retain stably at a given temperature; has enough Supersaturated solution- solution containing a higher amount of solute than is possible at a given temperature.

Solubility Solubility- is related to how well a solute can dissolve in a solvent. Solubility is usually shown along a line graph. When you look at the solubility curve, anything above the line doesn’t dissolve. Anything below that line has dissolved at a given temperature.

At 60°C, how many grams of KCl dissolves? At 60°C, how many grams of NaCl dissolves? At 60°C, how many grams of KNO3 dissolves? To dissolve 12 g of KNO3, what temperature is needed?

To dissolve 170g of KNO3, what temperature is needed? To dissolve 40g of KCl, what temperature is needed? To dissolve 50g of KCl, what temperature is needed?

•At 40°C, which types of solute are dissolved •At 40°C, which types of solute are dissolved? •At 80°C, how many grams of KCl dissolves? •Which solute has the highest variance in solubility? •Which solute isn’t affected much by the temperature?

Solution concentration refers to the quantity of solute dissolved in a specific quantity of solvent or solution. When finding solution concentration, you must have a solution as the denominator. (Remember: solvent + solute = solution) Solvent- the dissolver, ex. water Solute- what gets dissolved, ex. sugar. Ex. 5g salt x 100% = 5% salt solution 100g solution 10 g sugar x 100% = 10% sugar solution

Find the solution concentration of the following: 5 g of sugar + 95 g of water 10g solute + 90g of solvent 37g salt + 63g of water 900 g sugar + 100 g of water 80 g salt + 20g water 95 g solute + 205g water 75 g solute + 125g water 2g sugar in 100g solution 75g salt in 100g solution 20g solute in 200g solution 55g solute in 550g solution 10g solute/1000g solution 25g solute/250g solution

The Water Molecule: H2O Remember: water has many important physical properties-One of which is that it is a polar molecule. Polar-means that it has one side that is partially positive and one side that is partially negative. Electrons are not evenly distributed.

By having a partially positive and partially negative end, water is able to attack ionic compounds and dissolve them. One way to imagine how water acts upon an ionic compound is to think of tug of war. The + side of water tugs at the – side of the ionic compound; the – side of water tugs at the + side of the ionic compound. This is why water is a GREAT solvent.

Has mass and takes up space building blocks of matter Substance composed of 2 or more elements in fixed proportions that cannot be broken down. Chemical substance from which all others are made Material with uniform, definite composition Combination of substances in which materials retain their separate identities and can be physically separated Mixture not uniform Uniform mixture Mixture containing small solid particles Homogeneous mixture of 2 or more substances

pH The potential of hydrogen Is a way to measure the amount of H+ in acids and bases. pH values are from 0-14 pH 0-6  acid (have lots of H+) pH 7  neutral pH 8-14  base (have very little H+ )

Acids want to give away H+ ions. Acids have H+ ions. Bases want to take up H+ ions. Bases have OH- ions. When an acid combines with a base, it makes a salt and water. Acid + Base  Salt + H2O Ex. H+ + OH-  H2O pH values are from 0-14 pH 0-6  acid pH 7  neutral pH 8-14 base Acid Neutral Base stomach acid - 2 pure water - 7 blood - 7.5 cola drinks – 3 sea water - 8 tomatoes – 4 detergent - 10 milk - 6.5 household cleaners - 11 coffee – 5 oven cleaners - 14

Measuring pH Moving pH values: When you jump from one pH to the next pH, you increase the acidity or basicity by a factor of 10. Ex. pH4- pH5 We are increasing basicity by a factor of 10. Ex. pH 7- pH 9 We are increasing basicity by a factor of 100 (10 x10). Ex. pH 9 – pH 4 We are increasing acidity by a factor of 100,000 (10x10x10x10x10)