Acids and Bases An introduction if you forgot, and review if you remember!

Acids and Bases O Acids and Bases Video Acids and Bases Video O Note: you DO NOT need to know the pH math formula part!!!

Acids and Bases WS O Read through the information on the first page to learn about acids and bases O Once you’ve read through it, turn the page over and work through the Acids and Bases quiz O When you are finished, read pg in your text book O When you are finished, answer the Reading Check questions on pg. 225

Acids, Bases and Neutral O Acids are chemical compounds with a pH of LESS THAN 7 O Bases are chemical compounds with a pH of MORE THAN 7 O pH of 7 are NEUTRAL (neither acidic nor basic)

Examples of Acids O Stomach acid O Citrus fruits O Vinegar O Car batteries O Acid rain

Examples of Bases O Blood O Baking Soda O Drano O Egg Whites O Bleach O Soap

Properties of Acids and Bases ACIDSBASES -pH less than 7 -Sour taste -Corrosive -Turns blue litmus red -Contains hydrogen ions (H + ) -Usually has an H at the left side of the formula -Neutralizes bases to form a salt and water -pH greater than 7 -Bitter taste -Slippery, soapy and corrosive -Turns red litmus blue -Contains hydroxide ions (OH - ) -Usually has an OH at the right side of the formula -Neutralizes acids to form a salt and water

Identifying Acids 101 O Acids have hydrogen (H + ) ions in them, and are usually found at the far left of the formula O Example: HCl, H 2 SO 4, HNO 3, etc.

Identifying Bases 101 O Bases have hydroxide (OH - ) ions in them, and are usually found at the far right side of the formula O Example: NaOH, Mg(OH) 2, Ca(OH) 2, etc.

Warning!!! O Some acids/bases are corrosive (can burn through things) O You should NEVER test whether a solution is an acid or base by tasting or touching

But seriously don’t…

The Safe Way! O pH indicators are chemicals that change colours, depending on the pH of the solution they were placed in Examples: O Litmus paper O Methyl Orange O Bromothymol Blue O Phenophthalein O Indigo Carmine O Magnesium Ribbons

pH Indicators These indicators change color, depending on what they are put in:

Practice O What colour is litmus paper in an acidic solution? O What colour is bromothymol blue at a pH of 5? 7? 9? O Is a solution an acid or a base if you add methyl orange and it turns yellow? O Is a solution an acid or a base if you add phenolphthalein and it’s colourless?

Lab tomorrow! O Read the pH indicators lab and be prepared to perform this lab tomorrow. O O DO NOT LOSE, FORGET, or DESTROY this lab. It is the only copy you will get and if you do lose, forget or destroy it, you will have to write it all out BY HAND!