WATER

Molecules containing of Carbon. Define “Organic” – Molecules containing of Carbon.

Cow’s milk(C12H24O12) Nitrates (NO3-1) Water (H2O) Is it organic or not? Cow’s milk(C12H24O12) Nitrates (NO3-1) Water (H2O)

Water is an INORGANIC molecule Meaning it does not contain the element carbon

Water is the single most abundant compound in most living things Water covers ¾ of the Earth’s surface

There are 8 properties of water Polar Universal solvent Cohesion Surface Tension Adhesion Capillary action Specific heat capacity Density So lets figure out what they all mean

Quick Check: Get out your periodic table! What type of molecule is water? Draw the lewis dot stRucture

#1 Polar Molecule A molecule in which the charges are unevenly distributed is called polar molecule because the molecule is like a magnet with poles (uneven distribution of electrons between O2 and H atoms) The negative end is near the oxygen atom and the positive pole is between the hydrogen atoms DRAW the molecule in your notes

#2 Universal Solvent Why is your body mostly made of water? Because water is a polar substance it is able to surround solutes and break ions away-creating a SOLUTION Some materials do not dissolve when placed in water but separate into pieces so small that they do not settle out- creating a SUSPENSION Blood is both a solution (nutrients and minerals dissolved in it), and a suspension (cells and other particles) Body is mostly made of water so it can dissolve substances that enter body (nutrients, medicines) Ions, molecules with a charge

THE POSITIVE END IS ATTRACTED TO THE NEGATIVE END #3 COHESION An attraction between molecules of SAME substances is called COHESION THE POSITIVE END IS ATTRACTED TO THE NEGATIVE END Because of water is a polar molecule they can attract each other forming a HYDROGEN BOND

#4 SURFACE TENSION Cohesions explains (SURFACE TENSION) : why drops of water forms beads on smooth surfaces. why some insects and spiders can walk on a pond’s surface how water can overfill the lip of a glass Its called capillary action

#5 ADHESION An attraction between molecules of different substances is called ADHESION Water has a positive and a negative pole so it is able to attract particles and objects that have either charge Why when you spill a little water on a table your cup then seems to stick to the table

Know the difference

#6 CAPILLARY ACTION Adhesion explains: Capillary action: why water rises in a narrow tube against force of gravity (adhesion between the glass and the water molecule is stronger than the cohesion between the water molecules) - Reason why water goes up the roots and into stems and leaves of plants.

#7 Specific Heat Capacity It takes a great amount of energy to heat water up, but once heated water hold heat So, your body is like a car’s radiator. This why you need a hot water heater. Water takes a long time to heat up, so you need a reserve When blood flows heat is evenly distributed from the inside out. By heating water, it changes its state of matter. This helps the body distribute heat

#8 DENSITY WATER EXPANDS WHEN FROZEN THIS EXPLAINS WHY: Which makes its VOLUME more but keeps the mass the same. THIS EXPLAINS WHY: Water floats when frozen! Water expands when frozen, making the solid form less dense than the liquid form For it to become less dense it means it has to expand As states of matter change the speed of molecules change. The slower moving molecules allow the hydrogen bonds to hold longer. Water would sink to bottom, and would not melt-eventually it would build up and kill all aquatic life

What would happen if ice was more dense then the liquid form?

What would happen if ice was more dense then the liquid form?

Vocabulary Terms to Remember Organic- A substance that contains the element carbon Inorganic- A substance that does not contain the element carbon Polar and Polarity- A molecule in which opposites ends have opposite electric charges Cohesion- the tendency of molecules of the same kind to stick together Surface Tension- describes the net of water molecules on the top layer Adhesion- when molecules that are different stick together Capillary action- water’s ability to climb against gravity Specific heat capacity- water takes a long time to heat but will retain that heat for a long time Universal solvent- water dissolves most all substances Density- water is the only substance that becomes less dense when frozen