Mixtures, Solutions, Acids, and Bases

Mixtures Two or more substances (elements and/or compounds) combined but NOT chemically –each substance keeps its properties –Can be separated by physical properties Example: salt, sand, and water

Mixtures, Solutions, Acids, and Bases Heterogeneous mixture “Not well mixed”; different parts –Parts can be easily separated Salad

Mixtures, Solutions, Acids, and Bases Homogeneous mixture “Well mixed” –So well mixed that parts are difficult to separate Cake batter Video Heterogeneous or homogeneous?Heterogeneous or homogeneous?

Mixtures, Solutions, Acids, and Bases - Understanding Solutions What Is a Solution? Two parts to solutions: Solute: part being dissolved Solvent: part doing the dissolving A solution has the same properties throughout. It contains solute particles (molecules or ions) that are too small to see.

Mixtures, Solutions, Acids, and Bases What Is a Solution? Solutions can be made from any combinations of solids, liquids, and gases.

Mixtures, Solutions, Acids, and Bases - Understanding Solutions Colloids and Suspensions Colloids and suspensions are mixtures that have physical properties different from those of solutions. Colloid: small undissolved particles that never settle (permanently suspended) Suspension: particles settle out or can be filtered to separate

Mixtures, Solutions, Acids, and Bases Particles in a Solution When a solution forms, particles of the solute leave each other and become surrounded by particles of the solvent.

Mixtures, Solutions, Acids, and Bases Salt Dissolving in Water Activity Click the Active Art button to open a browser window and access Active Art about salt dissolving in water.

Mixtures, Solutions, Acids, and Bases Effects of Solutes on Solvents At 0ºC, pure water freezes, but water mixed with a solute does not. Solutes lower the freezing point of a solvent. Solid (frozen) water Liquid water solution

Mixtures, Solutions, Acids, and Bases Pure water boilingSalt Water Boiling Pure water boils at _______ degrees C? Salt water boils at _______ degrees C.

Mixtures, Solutions, Acids, and Bases Identifying Main Ideas A solution is a well mixed mixture that contains a solvent and at least one solute. The solvent is the substance present in the largest amount. A solute is a substance present in a smaller amount than the solvent. A solution has the same properties throughout. Main Idea A solution contains particles that are too small to see. Detail

Mixtures, Solutions, Acids, and Bases Universal Solvent Click the Video button to watch a movie about universal solvent.

Mixtures, Solutions, Acids, and Bases Concentration Amount of solute in a certain amount of solvent Concentrated: a lot of solute in solvent Dilute: a little solute in solvent Two ways to describe concentration: –Saturated: maximum amount of solute that can be dissolved more solute will form a precipitate –Unsaturated: less solute than could be dissolved Weak or dilute solutions –Very little solute dissolved

Mixtures, Solutions, Acids, and Bases - Concentration and Solubility Solubility Solubility is a measure of how much solute can dissolve in a solvent at a given temperature. A physical property used to identify substances –Solubility curves Soluble: solutes that can be dissolved Insoluble: solutes that will NOT dissolve in the solvent

Mixtures, Solutions, Acids, and Bases Which substance will dissolve exactly 100 grams of solute at 45 ◦ C? If you have 60g of Sodium Nitrate dissolved at 20°C, how much more of the salt will you have to add to make a saturated solution?

Mixtures, Solutions, Acids, and Bases Temperature and Solubility The solubility of the compound potassium nitrate (KNO 3 ) varies in water at different temperatures. - Concentration and Solubility

Mixtures, Solutions, Acids, and Bases Temperature and Solubility KNO 3 is least soluble at 0ºC. Reading Graphs: At which temperature shown in the graph is KNO 3 least soluble in water? - Concentration and Solubility

Mixtures, Solutions, Acids, and Bases Temperature and Solubility Approximately 65 g of KNO 3 are needed to saturate a water solution at 40ºC. Reading Graphs: Approximately what mass of KNO 3 is needed to saturate a water solution at 40ºC? - Concentration and Solubility

Mixtures, Solutions, Acids, and Bases Temperature and Solubility KNO 3 is about twice as soluble at 40ºC as it is at 20ºC. Calculating: About how much more soluble is KNO 3 at 40ºC than at 20ºC? - Concentration and Solubility

Mixtures, Solutions, Acids, and Bases Temperature and Solubility No; the curve shows that solubility increases more with each 20ºC increase in temperature. Interpreting Data: Does solubility increase at the same rate with every 20ºC increase in temperature? Explain. - Concentration and Solubility

Mixtures, Solutions, Acids, and Bases Links on Solubility Brainpop on mixtures vs. compounds

Mixtures, Solutions, Acids, and Bases Any substance that produces hydrogen ions (H+) when it dissolves. The chemical formula for acids start with “H” Acid

Mixtures, Solutions, Acids, and Bases Acid Properties Taste sour React actively with metals

Mixtures, Solutions, Acids, and Bases Acids Strong Hydrochloric (stomach acid) Sulfuric (battery acid) Weak Carbonic (carbonated drinks) Citric (citrus fruits)

Mixtures, Solutions, Acids, and Bases Base Any substance that produces hydroxide ions (OH-) when it dissolves. The chemical formula for bases end in “OH.”

Mixtures, Solutions, Acids, and Bases Base Properties Taste bitter Slippery to the touch Reacts with hair, etc. to remove clogged sinks

Mixtures, Solutions, Acids, and Bases Base Strong Sodium hydroxide (drain cleaner) Potassium hydroxide (in soft soap) Weak Ammonium hydroxide (household cleaner) Aluminum hydroxide (anti-perspirants)

Mixtures, Solutions, Acids, and Bases Acids and Bases in Solution The table lists some commonly encountered acids and bases.

Mixtures, Solutions, Acids, and Bases The pH Scale A low pH tells you that the concentration of hydrogen ions is high. In contrast, a high pH tells you that the concentration of hydrogen ions is low.

Mixtures, Solutions, Acids, and Bases Indicators Compounds which change color when mixed with an acid or base.

Mixtures, Solutions, Acids, and Bases Properties of Acids and Bases Litmus is an example of an indicator, a compound that changes color when in contact with an acid or a base.

Mixtures, Solutions, Acids, and Bases Litmus Red (pink) in acid. Blue in base.

Mixtures, Solutions, Acids, and Bases Phenolphthalein Colorless in acid. Pink in base.

Mixtures, Solutions, Acids, and Bases Hydrion Paper Use color scale. Red in acid to dark green in base. Shows pH.

Mixtures, Solutions, Acids, and Bases pH Click the Video button to watch a movie about pH. Brainpop on Acids and Bases

Mixtures, Solutions, Acids, and Bases Acid-Base Reactions A reaction between an acid and a base is called neutralization. An acid-base mixture is not as acidic or basic as the individual starting solutions. When acids and bases react a salt is formed

Mixtures, Solutions, Acids, and Bases Acid-Base Reactions Each salt listed in this table can be formed by the reaction between an acid and a base.

Mixtures, Solutions, Acids, and Bases Uses of Acids and Bases Acids and bases have many uses around the home and in industry.

Mixtures, Solutions, Acids, and Bases Strength of Acids and Bases Strong acids and weak acids act differently in water. Hydrochloric acid is a strong acid. Acetic acid is a weak acid.

Mixtures, Solutions, Acids, and Bases What Is Digestion? Chemical digestion breaks large molecules into smaller ones.

Mixtures, Solutions, Acids, and Bases pH in the Digestive System Foods are exposed to several changes in pH as they move through the digestive system.

Mixtures, Solutions, Acids, and Bases Graphic Organizer Solvents Solutions are made of dissolve in dissolve to form such as conduct do not conduct Solutes Molecules Water Electricity Ions