Pure Substances/Mixtures & Acid/Bases Benchmark SC.8.P.8.5  Recognize that there are a finite SC.8.P.8.8  Identify basic examples of and compare and classify the properties of compounds, including acids, bases, and salts. ESSENTIAL QUESTIONS: How can you differentiate between pure substances, mixtures, and solutions? What are the characteristics of acids, bases, and salts?

Bellringer Susie wants to make lemonade on a hot summer day. She mixes lemon juice, water, and sugar in a large container. Which of the following happens as she combines the ingredients? They mix together to form a new compound. They mix together to form a homogenous solution. The stirring motion causes them to break down into elements. The heavier items will not completely dissolve, creating a suspension.

Pure Substance Pure Substances can be an element from the periodic table or two or more elements chemically bonded together.

PS: Element These are chunks of all of the same type of atoms. You can easily identify elements because they are found on the periodic table.

PS: Compounds When two or more DIFFERENT elements are combined chemically by being bonded. Compounds turn into a new substance with completely new properties. EX. Sodium is a silvery substance that will explode when placed in water. Chlorine is a green gas that will dissolve your lungs. When they bond, they form salt which is completely different. + =

Mixtures: When two or more substances are combined physically (in the same place), but not chemically bonded together.

HETEROgeneous Mixtures: Two or more substances that are combined PHYSICALLY, but not chemically bonded. You get DIFFERENT amounts in each sample. Example: Chex Mix Italian Dressing Concrete

HOMOgeneous Mixtures (Solutions) When one substance is dissolved throughout another substance in equal amounts. You get the SAME amounts in each sample. Example: Coffee Air Sweet Tea

How do you change the color of hydrangeas?

They are everywhere.. In your food In your house EVEN IN YOU!!!!! Acids & Bases They are everywhere.. In your food In your house EVEN IN YOU!!!!!

What is an acid? An acid is a solution that has an excess of H+ ions. It comes from the Latin word acidus that means "sharp" or "sour". The more H + ions, the more acidic the solution.

Properties of an Acid Tastes Sour Conduct Electricity Corrosive, which means they break down certain substances. Many acids can corrode fabric, skin, and paper Some acids react strongly with metals Turns blue litmus paper red Picture from BBC Revision Bites http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_bases_1.shtml

Uses of Acids Acetic Acid = Vinegar Citric Acid = lemons, limes, & oranges. It is in many sour candies such as lemonhead & sour patch. Ascorbic acid = Vitamin C which your body needs to function. Sulfuric acid is used in the production of fertilizers, steel, paints, and plastics. Car batteries

What is a base? A base is a solution that has an excess of OH- ions. Another word for base is alkali. Bases are substances that can accept hydrogen ions

Properties of a Base Feel Slippery Taste Bitter Corrosive Can conduct electricity. (Think alkaline batteries.) Do not react with metals. Turns red litmus paper blue.

Uses of Bases Bases give soaps, ammonia, and many other cleaning products some of their useful properties. The OH- ions interact strongly with certain substances, such as dirt and grease. Chalk and oven cleaner are examples of familiar products that contain bases. Your blood is a basic solution.

pH Scale pH is a measure of how acidic or basic a solution is. The pH scale ranges from 0 to 14. Acidic solutions have pH values below 7 A solution with a pH of 0 is very acidic. A solution with a pH of 7 is neutral. Pure water has a pH of 7. Basic solutions have pH values above 7.

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.

Salts Salts (not table salt) result when an acid and a base neutralize each other (cancel each other out).

Acid – Base reactions Each salt listed in this table can be formed by the reaction between an acid and a base.

Acids and Bases Compare and Contrast Directions: Classify the various descriptions as being a characteristic of an acid or a base/alkaline

Exit Ticket when fat molecules are suspended in a solution Before today’s science class, Jose thought that salt was something that he uses to season his French fries. What is the scientific definition of “a salt”? when fat molecules are suspended in a solution the result when an acid and base are combined the particles that settle at the bottom of a solution when the pH of a solution is lower than 7 but higher than 3 Correct Answer: B