Biology. Properties of Water And Acids/Bases (pH) SB1.d. Explain the impact of water on life processes. Why is water important to humans?. 2/3 of the weight of a cell is WATER! Look at all the important uses of water in the body…. What properties of water make it so useful and important?.
Properties of Water
SB1.d. Explain the impact of water on life processes.
a. Has a slight charge on each end.
b. One side of water is “+” and the other side is “-”
c. This polarity enables water to dissolve many substances
2. Water is called “Universal solvent”:
a. Differences in charges pulls/pushes substances apart so they dissolve
3.Water is cohesive & adhesive which creates surface tension
Cohesive- water molecules stick to each other
Adhesive- water molecules stick to other surfaces
Surface tension- like a skin of water
Ex: how some insects walk on water
Surface tension created by cohesiveness of water
4. Water moves by capillary action
5. Water exhibits evaporative cooling:
6. Water expands during freezing:
Measures the concentration of Hydrogen (H+) ions in a solution
What is an ACID?
1. release H+ when mixed with water
2. 0-6 on pH scale
3. Sour, corrosive
4. Always have H at front of formula
5. Ex: HCl is hydrochloric acid
What is a BASE?
1. release hydroxide (OH-) when mixed with water
2. 8-14 on pH scale
3. Bitter, slippery, usually in cleaners
4. Always have OH at end of formula
5. Ex: NaOH is sodium hydroxide
Neutral: H+ ions and OH- ions are equal so it is neutral. They are 7 on pH scale.
1. Body chemicals that prevent sharp changes in pH so keep solution neutral
2. Help to control pH in blood, digestive tract, etc. to maintain homeostasis