which is the best to use to determine if something is an acid or a base: phenothalein, universal...

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Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish lab 2.Acid/base notes 3.Video

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Page 1: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Which is the best to use to determine if something is an acid or a base:

Phenothalein, universal indicator, or pH paper?

Agenda for Friday Oct 7th 1.Finish lab2.Acid/base notes3.Video

Page 2: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

What is pH

• Def - A value used to express how acidic or basic something is

• Look at how many hydronium or hydroxide ions– H3O+ or OH-

Page 3: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

pH Scale• the pH scale ranges between 0 and 14, with 7

being neutral

• A substance with a pH less than 7 is acidic.

• If greater than 7, the substance is basic or alkaline

• change in pH is a tenfold increase or decrease in the strength of the acid or base

Page 4: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Acid or base

• Acid – proton donor, increase in hydronium ions when added to water

• Properties– Sour in taste– Conducts electricity

Page 5: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Acid or base

• Base – proton acceptor, increase in hydroxide ions in water

• Properties– Bitter, soapy taste– Solutions feel slippery– Just as dangerous as acids

Page 6: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Acid – Base reactions

• Neutralization reaction – reaction with an acid and a base– Forms water and salt– Not all neutralization reactions produce neutral

solutions

Page 7: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Agenda for Monday Oct 10th 1. Neutralization of acid and base

Page 8: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Neutralizations

Page 9: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

The “used” water problem

Page 10: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Agenda for Tuesday Oct 11th 1. Acid rain

Page 11: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Acid Rain

• Robert Angus Smith, an English chemist, first used the phrase "acid rain" in 1852 – noted the connection between London's polluted

skies and the acidity of rain

• "normal" rainfall has a pH of 5.6

• Acid rain is defined as any form of wet precipitation which has a pH less than5.6

Page 12: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Sources of Acid Pollution• gases sulfur dioxide and various nitrogen oxides– primarily created by industrial factories, coal-fired

power, plants, and car emissions• Some scientists believe that natural sources (forest

fires, lightning, volcanoes, etc.) have an equally important effect

Page 13: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish

Sources Continued

• Areas where the soil has been disturbed (mines, forest fires, landslides, construction sites) may be making water more acidic

• Many soils are already acidic or contain minerals which react with rainwater, snow melt, etc., to form acids.

• The gases SO2 and NOx are thought to be carried long distances by air currents.

Page 14: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish
Page 15: Which is the best to use to determine if something is an acid or a base: Phenothalein, universal indicator, or pH paper? Agenda for Friday Oct 7 th 1.Finish