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What is chemistry?
the branch of science which studies matter and its changes due to the effects of energy
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What year was water proposed?
600 BC
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Who proposed water?
Thales
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What year was air proposed?
550 BC
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Who proposed air?
Anaximenes
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What year was fire proposed?
550 BC
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Who proposed fire?
Heraclitus
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What year was earth proposed?
450 BC
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Who proposed earth?
Empedocles
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What year was aether proposed?
350 BC
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Who proposed aether?
Aristotle
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What is the weight percentage of oxygen?
62
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what is the weight percentage of carbon?
20
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what is the weight percentage of hydrogen?
10
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What is the weight percentage of nitrogen?
3
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what is the symbol for sodium?
Na
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what is the symbol for potassium?
K
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What is the symbol for iron?
Fe
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what is the symbol for magnesium?
Mg
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What are atoms?
The smallest particles of elements which enter into chemical reactions
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For each kind of element there is a kind of?
isotope
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each atom consists of an inner region called the?
nucleus
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what orbits around the nucleus?
electrons
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protons have what kind of charge?
positive
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neutrons have what kind of charge?
no charge
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Both protons and neutrons are about how many times heavier than electrons?
1800 times
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within each atom the number or protons ____ the number of electrons?
equals
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atoms are?
electrically neutral
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what are ions?
when atoms gain or lose electrons they become negatively or positively charged
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The K shell is filled to capacity with how many electrons?
2
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what is the maximum number of electrons for a given shell (exception of the K shell) when it is in the outer shell?
8
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what are the two numbers that an atom is characterized by?
- 1. atomic number
- 2. atomic mass number
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the atomic number is?
the number of protons
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what is the atomic mass?
the number of protons plus the number of neutrons
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what are isotopes?
are atoms of the same element with different atomic masses
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What are the three different types of hydrogen?
- 1. Protium (ordinary hydrogen)
- 2. deuterium (heavy hydrogen)
- 3. Tritium (radioactive, radioisotope)
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what have tritiated compounds been used for?
to solve many problems in cell biology, for example, to elucidate the distribution of DNA to chromosomes during cell division
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What will determine the chemical activity of an element?
the number and arrangement of electrons
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why will atoms enter into reactions?
to achieve stable electronic configurations
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For atoms to achieve stable electronic configurations what can they do?
- 1. loss or gain electrons with the formation of ions
- 2. electrical unbalance
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why does oxygen exert a greater attraction for the shared electrons than the hydrogen nuclei?
because of its large more positive nucleus
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when the molecule as a whole does not have a net charge, within the molecule there is an unsymmetrical distribution of charge with the oxygen end of the molecule being more negative and the hydrogen end more positive what is it called?
polar covalent
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are all covalent compounds polar?
no
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CCl4 is ___ and ___
covalent and non-polar
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what is hydrogen bond?
type of chemical bond found in living systems that depends upon polar molecules
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DNA hydrogen bonds are typically displayed by?
an alpha helix
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what is the simplest way to determine whether a compound is ionic or covalent in nature?
test of relative electrical conductivity
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what does electrolyte mean?
can conduct electricity
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if it is an electrolyte it is also a ___
ionic compound
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what is a non-electrolyte?
when a compound cannot conduct electricity
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if a compound is non-electrolyte it is also a ___
covalent compound
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what are the 4 types of chemical reactions?
- 1. synthesis
- 2. decomposition
- 3. single replacement
- 4. double displacement
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what is oxidation?
free energy releasing (exergonic)
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what is exergonic?
free energy releasing
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what is reduction?
free energy absorbing (endergonic)
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what is endergonic?
free energy absorbing
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why is sugar oxidized in the cell (body)?
to provide energy
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what could occur in oxidation?
the removal of hydrogen from substances
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what is electron transfer?
transfer of electrons from one substance to another
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oxidation= ?
oxidation= removal of electrons
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reduction=?
reduction= addition of electrons
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reduction is endergonic or exergonic?
endergoinc
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Is oxidation endergonic or exergonic?
exergonic
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the oxygen consumed in degrading sugar in a cell acts as a what?
hydrogen acceptor (garbage collector)
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what are dissolved in the free water of cells?
inorganic substances
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what are 3 examples of inorganic substances?
salts, acids, and bases
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what is the charge of a cation?
positive
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what is the charge of the anions?
negative
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most important inorganic compounds in the cell are?
electrolytes
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what are acids?
compounds which release H+ when dissolved in water
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what are bases?
compounds which release OH- when dissolved in water
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what are salts?
upon dissolving produce + and - ions, none of which are H+ or OH- ions
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what cation and anion selected biological activity is fatal effects of high concentration?
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what 2 cations selected biological activity is nerve cell impulses?
Na+ and K+
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which cation is necessary for blood clotting?
Ca++
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which cation is necessary for activation of certain enzymes?
Mg++
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which cation and anion activity is nitrogen source for plants?
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which cation's activity is structure of cytochromes and hemoglobin (energy metabolism)?
Fe++
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what two anions activity is buffering action?
HCO3- and Co3=
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which anion has the activity of phosphorus source for plants?
PO4---
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Which anion has the activity of sulfur source for plants?
SO=4
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The relationship of H+ and OH- ions in a solution determines what 3 things?
- 1. neutrality
- 2. acidity
- 3. alkalinity
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what is mole?
A mole is the amount of an element equivalent to its atomic weight expressed in grams, or the amount of a substance equivalent to its molecular weight expressed in grams
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what is avogadro's number?
The number of particles per gram-atom and per mole. That number is 6.023 X 1023 atoms or moles, respectively
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the strength of an acid depends on what?
the concentration of H+ ions
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what is ph?
the negative log of the H+ concentration in moles/liter of solution
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solutions with pHs below 7 are?
acidic
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the pH of pure water at ordinary temperature is 7 so this is?
neutrality
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solutions with pHs above 7 are?
basic or alkaline
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what is the regular pH of the blood of humans?
7.4
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what could happen if the blood pH falls to 7.0?
acidic coma and death
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what happens when blood goes up to the pH of 7.8?
life terminates in tetany
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what are buffered solutions?
When the salt of a weak acid and the weak acid itself are dissolved in the same solution, the solution has the ability to react with both acids and bases
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what is Le Chatelier's principle?
when a system in equilibrium is disturbed by an external force, the equilibrium shifts in the direction which tends to neutralize the effect of the external force
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