Science 10 Mr. Jean January 3 rd, 2012

The plan: Video clip of the day What to look forward to in 2012 Science 10 review AcidsBases Chemistry Safety Video

Welcome Back: Things to look forward to in 2012

Total Solar Eclipse It doesn’t happen that often !! Next year, on November 13th, the Earth will witness a total solar eclipse

Closest known near miss: A NASA team has discovered that next year will be our closest asteroid miss EVER. The beast in question is named ‘433 Eros‘ and has been haunting our skies since its discovery in Come Jan 31st, if you’re looking in the right direction, you should be able to get a decent look.

Space Travel for a price: Scheduled to kick off in 2012 is COMMERCIAL SPACE TRAVEL. Yes, that’s right. Come October 2012, tickets will be on sale for you to get your very own space cadet feeling. However, at a cool $200,000.

And of course: Science 10 stuff: –Chemistry test next week. Topics will be given out tomorrow Topics will be given out tomorrow –Weather Unit –No exam; however…. There will be two tests at the end of the semester. Test #1: Chemistry & Weather (15% of final grade) Test #2: Physics & Biology (15% of final grade)

Acids, Bases and Salts

Acids Acids are very important substances. They are why lemons taste sour. They digest food in our stomachs. They dissolve rocks to make fertilizer. They dissolve tooth enamel to form cavities.

H 2 SO 4 (aq) Sulfuric Acid: H 2 SO 4 (aq) Sulfuric acid is the most common chemical manufactured in the United States. 80 billion pounds are used every year in the States to manufacture fertilizers, detergents, plastics, pharmaceuticals, storage batteries and metals.

What do these things have in common?

Acids They taste sour. As a matter of fact, the word acid comes from the latin term “acere” which means sour. If you check the ingredients of many foods, you will see that they may contain acetic acid (vinegar ) and citric acid (found in oranges).

The Bad and the Ugly

Acid Rain Nature does produce acid-forming compounds. Volcanoes, for example, produce SO 2 Unfortunately, industries produce far greater quantities of it. SO 2 + H 2 O  H 2 SO 3(aq) Roughly 2/3 of all SO 2 and ¼ of all NO x produced come from electric power generation that relies on burning fossil fuels such as coal.

Effects of Acid Rain It causes the acidification of lakes and streams and contributes to the damage of trees at high elevation and many sensitive forest soils. It also accelerates the decay of building materials and paints. z/acid_rain.htm z/acid_rain.htm

Acid Raindrops Are Falling on My Head…how to stop this… We can use scrubbers which chemically remove the SO 2 from coal-burning industries, and power plants can switch to alternative fuels (such as solar, wind, water, or nuclear energy.)

Each Individual Can Help Turn off lights, computers, and other appliances when you're not using them. Turn off lights, computers, and other appliances when you're not using them. Only use electric appliances when you need them. Insulate your home as best you can. Insulate your home as best you can. Carpool, use public transportation, or better yet, walk or bicycle whenever possible. Carpool, use public transportation, or better yet, walk or bicycle whenever possible. Buy vehicles with low NOx emissions, and maintain all vehicles well. Buy vehicles with low NOx emissions, and maintain all vehicles well. Be well-informed. VOTE for GOVERNMENT’S which care about the environment. VOTE for GOVERNMENT’S which care about the environment.

Bases A major use for bases is in cleaning. Soaps and detergents are basic. Bases also help make soils and lakes less acidic. For instance, in order to increase the pH of soil, we can add lime (CaO) or chalk. This use in agriculture is why gypsum is technically not considered a mineral…farmers would dig it up out of their fields and use it for conditioning their soil.

Bases How do bases feel and taste?

Characteristics of Bases Bases are bitter (if edible) They feel soapy (bases make soaps!) They turn red litmus paper blue They neutralize acids Recognized by a metal with hydroxide Ie NaOH, NH 4 OH, LiOH etc

Characteristics of Acids Sour taste (if edible) Turn blue litmus paper red React with active metals to produce hydrogen gas Conduct electricity Neutralize bases Feel slippery – like your fingerprints have been dissolved away…

Salts They conduct electricity but do not change the color of litmus paper. These are formed by any reaction of a base and an acid – the products are always water and a salt (ionic substance).

Chemistry Safety Video: Super fun mandatory safety video! Units/Measurements/LabSafety.htm Units/Measurements/LabSafety.htm