what do you know about this equation? c 6 h 12 o 6 + 6o 2 6co 2 + 6h 2 o what elements are...

What do you know about this equation?

C6H12O6 + 6O2 6CO2 + 6H2OWhat elements are present?

How many of each are there?

What compounds are involved?

What is this an equation for?

The Nature of Matter2-1

I. AtomsA. Greek for “unable to be cut”B. 100 million atoms in a row = 1 cmC. Made up of subatomic particles:

1. protons (+)2. neutrons (no charge –

neutral)3. electrons (-)

II. ElementsA. Substances made up of only one kind of atom

1. over 100 known elements2. only about 20 found in living

things3. atomic # = number of protons

(or electrons since they are equal)4. The most abundant elements in

living things are CHNOPS

BSi

Ge AsSb Te

At

http://www.youtube.com/watch?v=r7hO-1ItqXw

III. Chemical CompoundsA. A substance formed by the chemical

combination of two or more elements in definite proportions

B. Examples : H2O, NaCl

C. Properties of the compound can be different than those of the element

Example 1: H and O are gases but together they are liquid

Example 2: Cl alone is a poisonous gas but with Na it creates harmless salt

IV. Chemical BondsIV. Chemical BondsA. All atoms want to have 8 “valence electrons” in their outer shell in order to be happy. If they don’t they often bond with other atoms.

V. Ionic BondingV. Ionic BondingA. When one atom donates electrons to another. B. Some atoms like to lose electrons to make a shell of 8 and others like to gain them (usually happens between metals and non metals)

Ionic Bonds between Na and Cl

VI. Covalent BondingVI. Covalent BondingA. Electrons are shared instead of lost or gained to form a molecule.B. Single bond - sharing a pair (2) electrons

C. Double = sharing 2 pairs (4) electrons

VII. Hydrogen Bonds Water molecules have very special

properties that attract them to one another

These weak bonds (attraction) between water molecules are called Hydrogen bonds

Why Discuss WATER?

• All living things depend on it.

• Over 60% of the human body is water

https://www.youtube.com/watch?v=nSENolWbyYQ

VIII. The Water MoleculeVIII. The Water MoleculeA. H2O = held together by covalent bonds

B. Oxygen is bigger so the electrons are shared but unequally. Oxygen becomes slightly negative and hydrogen, slightly positive.

C. This makes water a polar molecule(it has a slightly + and – side!)

https://www.youtube.com/watch?v=zCheAcpFkL8

Draw a picture in your notes of two water molecules interacting. Label the charges on oxygen and

hydrogen atoms, and label the hydrogen bond between the water molecules.

IX. Cohesion1. Cohesion – the attraction between molecules of the samesame substanceExample: Water sticking to other water molecules!

2. Responsible for surface tension

3. Adhesion – attraction between molecules of different substances

Example: Water sticking to a leaf

X. Adhesion

4. Capillary Action- ability of a liquid (WATER) to flow in narrow spaces against gravity due to adhesion and cohesion.Example: water moving up roots/stems of plants!!

Capillary Action

XI. Adhesion and Cohesion play a role in Plants!

XII. Polar VS. Non-Polar

Polar molecules are not attracted to non-polar molecules like oil

Do NowWhat are the weak bonds that form between two or more water (H2O) molecules?

Today’s Objective To observe the properties of water (cohesion

and adhesion) in a Water Lab. Water is vital for living things and cellular

processes.

1. Go over lab procedure 2. Distribute supplies 3. Complete lab (Part 1) and answer

questions 4. Clean up and review findings

Exit Card What is the difference between adhesion

and cohesion? Can you name the steps of the water

cycle? How might cohesion play a role in the

water cycle?