U2 S2 L5 Acids around you Read online material

Upon completion of this lesson, you should be able to: state general examples of how are lives are affected by acid-base chemistry analyze society’s influence on scientific and technological endeavours using examples from acid-base chemistry construct arguments to support a decision and recognize various perspectives concerning the topic of acid deposition define a buffer according to both its components and its function. recognize that blood is a buffered by a carbon dioxide - bicarbonate buffer, and that without this natural buffering effect within our blood, homeostasis would not be maintained identify and describe science and technology based careers related to acid- base chemistry

Have you ever been stung by a bee or a wasp? Bees and wasps inject venom into you when they sting. –A bee's venom is acidic, –a wasp's is basic. Given what you already know about household acid-base reactions, how would you treat a bee sting? Could you use the same treatment to sooth wasp sting?

Can one plant produce two completely different flower colours? The colours of many flowers are pH dependent. Hydrangea's are particularly sensitive to soil pH. At pH 5.5 or lower, the flowers are blue in colour, however at pH 6.0 or higher soil, the flowers are pink! Adding lime to increase the pH of the soil around a hydrangea brings out the blue colour while adding sulfur to lower the pH brings out the pink colour

Antacids Gastric acid, HCl, creates the acidic environment that allows enzymes to digest food. Heart burn is the term that describes a condition caused by excess gastric acid in your stomach. There are many different antacids on the market. They all have one thing in common, they are all bases that neutralize the HCl. Examples of bases found in antacids are: calcium carbonate magnesium hydroxide sodium hydrogen carbonate.

Acid Rain Acid deposition - commonly called acid rain - is caused by emissions of sulfur dioxide and nitrogen oxides. Although natural sources of sulfur oxides and nitrogen oxides do exist, more than 90% of the sulfur and 95% of the nitrogen emissions occurring in eastern North America are of human origin. These primary air pollutants arise from the use of coal in the production of electricity, from base-metal smelting, and from fuel combustion in vehicles. Once released into the atmosphere, they can be converted chemically into such secondary pollutants as nitric acid and sulfuric acid, both of which dissolve easily in water. The resulting acidic water droplets can be carried long distances by prevailing winds, returning to Earth as acid rain, snow, or fog."

No Pain, No Gain Have you ever exercised to the point where your muscles get that "burning" sensation? Your muscles get energy from ATP. ATP is produced by the respiration (burning) of glucose or glycogen. A bi-product of respiration is lactic acid. The burn you feel during intense exercise is caused by a build-up of hydronium ions in your muscle cells and surrounding blood. The hydronium ion build-up occurs when your blood is not able to deliver enough oxygen to your muscles. Hydronium ions are produced by the ionization of lactic acid.

Buffers A buffered solution maintains its pH at a fairly constant level when limited amounts of strong acid or strong base are added to it. The buffer solution must be able to neutralize both the addition of the acid and a base. A buffer is a mixture of an acid and its conjugate base. (base and conjugate acid) –Weak acid / salt of conjugate base. Acetic acid / sodium acetate Carbonic acid / sodium bicarbonate –Weak base / salt of conjugate acid. Ammonia / ammonium chloride

Maintaining Blood pH: the Carbon Dioxide-Bicarbonate Buffer Blood contains a buffer system. –The addition of just 0.01 mol of HCl to 1.0 L of naturally buffered blood causes a pH decrease from about 7.4 to 7.2. –Whereas the addition of the same amount of HCl to 1.0 L of a saline solution causes the pH to drop from 7.0 to 2.0. –In other words, the [H 3 O + ] change for saline solution (5.0 pH units) is about 80,000 times greater than the pH change of the blood (0.2 pH unit). The ability of human blood to neutralize added hydronium or hydroxide is essential. A decrease of just 0.20 pH units reduces the ability of red blood cells to carry oxygen. A change upwards or downwards of 0.40 pH units can cause death

The blood Buffer: carbonic acid/hydrogen carbonate