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- is anything that occupies space.
- Matter is made of one or
- more elements.
An element is the most pure form of matter. Elements are made of atoms.
- Certain elements are needed
- in trace amounts. These are also essential to life.
- Eg. The human body needs
- trace amounts of boron, chromium, iron, iodine, etc.
have a positive charge (p+)
have a neutral charge.
have a negative charge.
number of protons (also number ofelectrons)
number of protons + number of neutrons
- different isotopes of an
- element have the same atomic # but different atomic weights. Example: Carbon –
- 12, Carbon – 13 and Carbon – 14 all have the same # of protons (i.e. 6
- protons), but, # of neutrons vary. C12 has 6 neutrons, C13has
- 7 neutrons and C14
- has 8 neutrons. Hence they all have the same molecular number, ie. 6, but
- different atomic weights: viz. 12, 13 and 14, respectively.
Compounds are made up of 2or more elements or molecules in a fixed ratio.Elements are rarely foundas such in nature. They are generally found as compounds.Many compounds are made upof only 2 elements. Eg. Table salt (NaCl).In living organisms,compounds are made up of 3 – 4 different elements. Eg. Proteins are made up ofC, H, O and N.
Three type of bonds
- 1Ionic bonds
- 2Covalent Bonds
- 3Hydrogen Bonds
- Ionic Bonds form between
- atoms that have formed ions. An ion forms
- when an atom looses or gains an electron.
Ionic bonds form polar molecules that can dissolve in water. They are considered hydrophilic in nature, meaning water loving.
- Covalent Bonds form when two atoms share electrons
- to complete the outer complete orbit. Covalent bonds can be polar or non-polar
Polar covalent bonds
when sharing in unequal (oxygen and two hydrogen atoms form water, the sharing is unequal).This creates a polar compound with unique properties. One end is slightly negative the other slightly positive.
Non-Polar covalent bond
forms when sharing is equal,the molecule has no charge (i.e. hydrocarbons are components of fats). These compounds are hydrophobic, or waterfearing. When oxygen bond to another oxygen. Electrons are shared equally.
occur when polarcovalent bonds produce slightly negative and slightly positive charges thatattract one another.
three different states of matter
solid (ice), liquid (water) and gas (water-vapor).
Properties of Water
- Water has a high surface tension.
- Hence, it acts as an unbroken film to water insects.
- Water is adhesive: it is
- attracted to different substances.
- Water is highly cohesive.
- Cohesion is the attraction of water to itself. Hence the tree-sap rises up in
- an uninterrupted flow from the roots to the leaves.
- Water conducts heat and is a great evaporative cooler
- due to two properties:
- It has a high specific heat which allows it to absorb a lot
- of heat
- It has a high heat of vaporization which allows it to moderate
- Water is a universal
- solvent; Hence,
- just about anything can dissolve in water.
- Ice is less dense than liquid water. Ice crystals have a much more
- spaceous arrangement of water molecules compared to the structure of liquid
pH by definition is a measure of the hydrogen ion concentration in a solution.
The pH ranges from 0-14
- the concentration of H+ = concentration of OH- then the pH is neutral = 7
- the concentration of H+ > concentration of OH- then the pH is acidic < 7
- the concentration of H+ < concentration of OH- then the pH is basic > 7
are substances that help to maintain a constantpH. All cells are buffered. Human bloodis buffered with carbon dioxide and stays at approximately 7.3.
The 4 common macromolecules
- 1. Carbohydrates are polymers of sugars(saccharides). They have a carbon:hydrogen:oxygen ratio of 1:2:1
- 2. Lipids
- 3. Proteins
- 4. Nucleic Acids
in plants Primary Metabolism includes
- Cell Respiration
- Metabolism that involves the making of the 4 macromolecules
Characteristics of Life
- · Composed of Cells
- ·Acquires, stores and uses energy(via metabolism)
- ·Responds to Stimuli(Irritability)
- ·Maintains constant internalenvironments (Homeostasis)
- ·Reproduces independently usingDNA “Heredity”
Levels of Organization in
The Dependent Variable
is whatthe researcher measures. It is plotted on the Y-axis.
The Independent Variable
is thefactor that may or may not produce a effect. When properly done it includes a Test or Treatment Group and a ControlGroup. The independent variable isplotted on the X-axis.
- A hypothesis is a proposed explanation
- for a set of observations. A good hypothesis leads to predictions
- that scientists can test by recording additional observations
- or by designing experiments.
How is a theory different
from a hypothesis?
- A scientific theory is much broader in scope than a hypothesis. It is usually general enough to generate many new, specific hypotheses that can then be tested. And a theory is supported by a large and usually growing body of evidence. Theories that become widely adopted (such as the theory of evolution) explain a great diversity of observations and are supported by a vast
- accumulation of evidence.
- Atomic #12
- Atomic Weight 24.30
- Atomic # 3
- Atomic Weight 6.941
- Atomic #10
- Atomic Weight 20.18
- Atomic #1
- ATOMIC WEIGHT 1.0079
- ATOMIC #8
- ATOMIC WEIGHT 15.99
- ATOMIC # 7
- atomic weight 14.007
- ATOMIC # 6
- ATOMIC WEIGHT 12.011