Presentation on theme: "Take out a scrap piece of paper… List 2 acids and 2 bases."— Presentation transcript:
Take out a scrap piece of paper… List 2 acids and 2 bases
By the end of today you should be able to… Define acid, base, pH, and buffer Describe why substances below a pH of 7 are acidic and why substances above a pH of 7 are basic Describe 2 examples of pH in your body
A solution is… ◦ A mixture where all the components are evenly distributed (salt water) When substances like salt or sugar dissolve in water the break up into ions ◦ NaCl Na + and Cl - Sometimes we call ions electrolytes ◦ Like in Gatorade!
A molecule of water (H 2 O) can break apart as well H 2 O H + and OH - Number of positive ions = number of negative ions So water is Neutral
pH Scale – a measurement system used to show the amount of H + in a solution “potential hydrogen” 0 – 14; pH of 7 has equal parts H + and OH - That’s why H 2 O is neutral! What if H + and OH - weren’t equal?!
Acid – a compound that forms H + ions when in a solution Contain more H + ions than pure water Have a pH value below 7 The lower the pH, the stronger the acid Taste sour or tangy
Base – a compound that forms OH - ions when dissolved in a solution Contain fewer H+ ions than pure water pH value above 7 The higher the pH the stronger the base Make your skin feel slippery
Buffer – a substance that helps to prevent sudden changes in pH This is especially useful in the body where some chemical reactions only work at certain pH levels
We use acids and bases in every day life ◦ Many household cleaners are bases ◦ Some of the foods we eat are acids ◦ Farmers must maintain the pH of the soil ◦ We monitor the pH of our swimming pools
Digestion ◦ Stomach acid has a pH of 1-2 ◦ This is necessary to break down the foods we eat Blood ◦ Blood has a pH around 7.4 ◦ pH plays an important role in the amount of oxygen carried by your blood
Enzymes ◦ pH is extremely important to enzymes ◦ Enzymes control almost all chemical reaction in your body ◦ They will only work at specific pH levels!
A change of pH of 1 is 10x the concentration of H + ions pH of 4 has 10 times as many H + as a pH of 5!
A pH of 6 is how many times more acidic than a pH of 8? pH of 3 is how many times less acidic than a pH of 2? pH of 12 is how many times less acidic than a pH of 4?