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Some basic chemistry
- For Human beings:
- O = 65.0%
- C = 18.5%
- H = 9.5%
- N = 3.3%
- Ca = 1.5%
- K = 1%
- S = 0.3%
- Na = 0.2%
- Cl = 0.2%
- Mg = 0.1%
- The following are Less the 0.01%
- B, Cr, Co, Cu, F, I, Fe, Mn, Mo, Se, Si, Sn, V, Zn
Trace Elements: are required but only in very small amounts, but you can not live without them. (They are the elements with less then 0.01% of the human body).
Matter: Anything that occupies space and has mass.
Elements: substances that cannot be broken down into other substances; Matter is composed of elements.
Compounds: substances that contain two or more elements in a fixed ratio. [elements combine to make compounds]
- Atom: the smallest unit of matter that still retains the properties of an element.
- named from the Greek word meaning "indivisible".
Proton: A subatomic particle with a single unit of positive electical charge (+).
Electron: A subatomic particle with a single unit of negative electrical charge (-).
- Neutron: A subatomic particle that has a neutral electrical charge.
- [No Charge]
- Nucleus: An atoms central core, contains protons and neutrons.
- NOT ELECTRONS!
- Atomic Number: is equivalent to the number of protons in an atom.
- Also tells you the location on the periodic table.
- Mass: is a measure of the amount of material in an object.
- Mass never changes, weight changes depending on the gravitational pull.
- Mass Number: is the sum of protons and neutrons in its nucleus.
- Also shown on the periodic table on the bottom typicaly.
- Isotopes: an element that has the same number of protons and electrons, but a different number of neutrons.
- in other words, isotopes are the same element with a different Mass.
How many of the 92 naturally occurring elements are used by living organisms?
Which four are the most abundent in living cells?
- Oxygen (O), Carbon (C), Hydrogen (H), and Nitrogen (N).
Which of the following are compounds?
Oxygen Gas (O2)
Why or why not?
H2O and CH4 are because they have at least two elements. Oxygen is not becaouse there is only one element (diatomic).
Radioactive isotope: the necleus decays , giving off particles of energy.
By definition, all atoms of Carbon have exacly six ________, but the number of ________ varies from one isotope to another.
By definition, all atoms of Carbon have exacly six protons, but the number of neutrons varies from one isotope to another.
As two atoms approach each other, which subatomic particles will first come into contact?
The Electrons of the outermost shells.
- Chemical bonds: An attraction between two atoms resulting from a sharing of outershell electrons or the presence of opposite charges on the atoms. The bonded atoms gain complete outer electron shells.
- The three types of bonds:
- Ionic: Strongest (oppisitsn attract)
- Covalent: share 1 or more pairs, (completion) form molecules
- Hydrogen: are F,O,N
Ionic bonds:[strongest]; An attraction between two ions with oppisite electrical charges. The electrical attraction of the oppisite charges holds the ions together.
- Hydrogen bonds: A type of weak chemical bond formed when a partially positive hydrogen atom from one polar molecule is attracted to the partially negitive atom in another molecule (or in another part of the same molecule).
- Hydrogen bonds are strong dipole attraction between F,O,N & H
Covalent bonds: An attraction between atoms that share one or more pairs of outershell electrons. (sharing is caring).
When a lithium ion (Li+) joins a bromine ion (Br-) to form lithium bromide, the resulting bond is a(n) _______ bond.
When a lithium ion (Li+) joins a bromine ion (Br-) to form lithium bromide, the resulting bond is an IONIC bond.
Polar molecule: a molecule containing polar covalent bonds (having opposite charges on opposite ends).
Predict the formula for the compound that results when a molecule of sulfur trioxide (SO3) combines with a molecule of water to produce a single molecule of product.
- SO3 + H2O --> H2SO4 Sulfuric Acid
Generic chemical equation
- Reactants ---> Products
- always left --> always right
Heat: The amount of energy associated with the movement of the atoms and molecules in a body of matter.
Temperature: measures the intensity of the heat.
Evaporative cooling: When a substance evaporates (changes froma liquide state to a gas state), the surface of the liquid remaining behind cools down.
- Solvant(more) + Salute(less) = Solution;
- A liquid consisting of a homogeneous mixture of two or more substances: a dissolving agent, the solvent, and a substance that is dissolved, the solute.
Explain why ice floats.
Ice floats because it is less dense then liquid because the more stable hydrogen bonds lock the molecules into a spacious crystal.
Explain why, if you pour very carefully, you can actually "stack" water slightly above the rim of a cup.
Surface tension; due to waters cohesion will keep the water from spilling over
- Acid: A chemical compound that releases H (Hydrogen).
- PH < 7
- 0 is the strongest acid
- Base: A compound that accepts H (Hydrogen).
- 7 < PH
- 14 is the strongest Base
- PH scale:
- Acidic < 7 < Basic
- [H+] [OH-]
- Neutral: [H+] = [OH-]
- or a PH = 7