Unit 4

 Two or more substances together  Mixture of two solids ◦ Spoonful of salt mixed together with a spoonful of baking soda.  Mixture of two liquids ◦ Cup of olive oil and a cub of vinegar  Mixture of a solid and a liquid ◦ Sand in an aquarium full of water

SaltBaking Soda Salt and Baking Soda Mixture

 Simplest kind of interaction  Pieces of the two substances are randomly interspersed and they come to rest against one another  Two kinds of particles coexist and are completely unaffected by being close with one another  Two substances are still identifiably distinct

 When mixed and shaken, the two liquids are distributed throughout one another in tiny droplets  When mixing stops, the two substances rejoin other droplets of their own kind and reassemble themselves into two individual substances  Two substances are still identifiably distinct

 Water still a pure continuous mass, but now infused with sand chunks  When mixing stops, gravity pulls on sand to settle at the bottom  Every surface of the sand is in contact with the water  Substances still coexist independent of one another

 To incorporate one substance uniformly into another substance at the particle level  Example ◦ Sugar and water

 A mixture formed when one substance dissolves in another  What dissolves is known as the solute  What the solute dissolves into is the solvent

 Between the sugar and the water, which is the solute and which is the solvent? Solute? Sugar Solvent? Water

 The Air ◦ SolventNitrogen gas ◦ SoluteOxygen gas  Brass ◦ SolventCopper ◦ SoluteZinc

 Copper (Solvent) + Zinc (Solute) = Brass

 The amount of solute dissolved in a measure of solvent  Imagine two beakers with 100 mL of water in each. One has 5g of sugar, the other 10g of sugar

5g Sugar10 g Sugar

 How are the two solutions the same?  Answer ◦ Both contain water and sugar ◦ Both are clear ◦ Same amount of Water

 How are the two solutions different?  Answer ◦ Amount of solute (sugar)

 1st – Mass Ratio ◦ Ten grams of sugar in 90 g of water produces a 10% sugar solution  Total mass = 10g + 90g = 100g  10g sugar divided by 100g = 10%  2nd – Parts per thousand or Parts per million ◦ Every liter (1000mL) of seawater contains 19 g of chlorine particles. ◦ So there are 19 parts per thousand of chlorine in seawater

 Saturated – a solution with the maximum amount of dissolved solute  A fixed amount of water will dissolve a certain amount of sugar.  If more sugar is added, it will not dissolve, but fall to the bottom of the container.