The Chemical Level Flashcards
What is chemistry?
The study of structure and interaction of matter
What is biochemistry?
the chemistry of living organism’s and life processes
What is biochemistry also known as
biologic chemistry or physiologic chemistry
What is matter
anything that occupies space and has mass
What is mass?
Any amount of matter in any object
Matter on Earth exists in what forms?
solid, liquid, gas
All forms of matter are made up of what?
chemical elements
True or False: each chemical element can be split into simpler substances by ordinary chemical means
False: each chemical element can’t be split into simpler substances by ordinary chemical means
How many naturally occurring elements exist?
92
How many man-made elements exist?
25
How are elements designated?
chemical symbols
How many naturally occurring elements is the body made up of?
25
How many naturally occurring elements constitute 95% of bodys mass? What are they?
4, carbon, hydrogen, oxygen and nitrogen
How much of the bodys mass does carbon, hydrogen, oxygen and nitrogen make up?
95%
What/how many elements contribute to 3.6% of bodys mass?
8:calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium, iron
How much of bodies mass does Ca, P, K, S, Na, Cl, Mg and Fe make up?
3.6%
How many elements account for 0.4 % of bodys mass? What are they and what are they called?
14 race elements: aluminum, boron, chromium, cobalt, copper, flourine, iodine, manganese, molybdenum, selenium, silicon, tin, vanadium, zinc
What is an atom?
smallest units of matter that retain the properties and characteristics of an element
What is a nucleus?
dense central core with two subatomic particles
What are the subatomic particles contained in the nucleus of an atom?
protons and neutrons
What are protons?
carry a positive electrical charge
What are neutrons?
carry no charge
What are electrons?
carry a negative electrical charge
Where are electons contained in an atom?
in electron shells found around the nucleus
What is the maximum number of electron shells that an atom can have?
7
True or false: any amount of electrons can reside in an electron shell
False: each electron shell can hold a fixed number of electrons
What is the maximum amount of electrons that can be held in the first electron shell?
2
What is the maximum amount of electrons that can be held in the second electron shell?
8
What is the maximum amount of electrons that can be held in the third electron shell?
8
What is the maximum amount of electrons that can be held in the fourth electron shell?
18
What is the maximum amount of electrons that can be held in the fifth electron shell?
18
What is the maximum amount of electrons that can be held in the sixth electron shell?
32
What is the maximum amount of electrons that can be held in the seventh electron shell?
32
The chemical properties of an atom are a function of what?
its electrons
What causes an atom to be electrically neutral?
carrying an equal amount of protons and electrons carry a charge of zero
What is the atomic number
equal to number of protons, distinguishes atoms from each other
What is a mass number
the sum of protons and neutrons of an atom
True or false:all atoms of an element have the same atomic number
true
Can atoms of the same element have different number of neutrons
yes, those atoms have a different mass number but electrons remain the same
What are isotopes?
atoms of the same element with different mass number
What are radioactive isotopes?
unstable and decay into simpler more stable configuration, as they decay they emit radiation
Do radioactive isotopes stay the same element as they decay?
in the process of decay often become different elements
What type of radiation do radioactive isotypes emit?
either subatomic particles or packets of energy
What is the standard unit used to measure the mass of an atom?
dalton
One dalton equals:
1/16 of the weight of one atom of O2
What is the mass of a neutron?
1.008 daltons
What is the mass of a proton?
1.007 daltons
What is the mass of an electron?
0.0005 dalton
What is atomic mass (atomic weight)?
average weight of all its naturally occurring isotopes
What is the periodic table
known chemical elements listed
How is the periodic table arranged?
in rows left to right in order of their atomic number
How many horizontal rows are on the periodic table? What are those rows called?
period: #1-7
What does a period on the periodic table represenet?
the number of the period represents the number of electron shells of an element, all elements in a given period have the same number of electrons shells as their periods number
What is each column of the periodic table called? How many columns and how are they numbered?
numbered I - VIII is called a group
What do groups of the periodic table represent?
elements in each group share the same chemical properties, all elements in a group have the same number of electrons in the outermost shell (1-8)
What are ions?
atoms electrically charged negatively or positively (gives up or gains electrons)
How can an atom be positively or negatively charged?
the unequal number of electrons and protons provides - or + charge to an ion
What is a compound? Give three examples
a substance made or two or more atoms that can be broken down into two or more different elements by ordinary chemical means
ie.h2O, NaCl, Urea
What are chemical bonds?
forces that hold the atoms close together to form molecules or compounds
What determines the likelihood that one atom will form a chemical bond with another?
depends of the number of electrons in its valence electron shell
What is a valence electron shell
outermost electron shell
What makes an atom chemically stable?
when holding 8 electrons in a valence shell, unlikely to form chemical bonds
is the first electron shell chemically stable with 8 electrons?
no, with two
Are atoms that are the most biologically important chemically stable?
no, atoms that are most biologically important do not have eight electrons in valence shell
What is the octet rule?
under proper circumstances 2 or more atoms can interact to produce a chemically stable arrangement of 8 valence electrons for each atom
What are elements in group VIII called? Why?
noble gases, all of them have 8 electrons in valence shell and are not chemically reactive, they have met the octet rule
When are chemical bonds formed?
when one atom interacts with another to form a bond if the result will leave both chemically stable
What determines the type of chemical bond will result between two atoms?
the way the electrons are distributed between the atoms
What is a cation?
by losing valence electrons the atom becomes an atom with a positive charge
What is an anion?
by gaining valence electrons the atom become an ion with a negative charge
What is an ionic bond?
+ and - charged ions are attached to one another
What are ionic compounds? GIve an example
exist as solids in the form of crystals, ie NaCl
In the body compounds with ionic bonds are found where?
bones and teeth, most other ions are dissolved in body fluids
What happens to ionic compounds when dissolved?
they dissociate
What is ionic compound dissociation?
an ionic compound that dissociates in a solution breaks down into positive and negative ions, then called electrolytes
What happens to electrolytes in the body?
ions surrounded by water molecules
What are molecules?
electrons shared between two or more atoms, can be between two of the same or different atoms
What is a covalent bond?
atoms form a molecule by sharing 1, 2, or 3 pairs of valence electrons, neither of combing atoms loses or gains electrons
What makes a covalent bond stronger?
the greater number of electron pairs shared the stronger the covalent bond
What are the most frequent chemical bonds in the body?
covalent bonds
What are the types of covalent bonds?
polar or non polar
What is a polar covalent bond?
electrons not shared equally so one part of the molecule is more negative than the other, molecules will present two poles (-and+)
Are polar molecules hydrophilic or hydrophobic?
hydrophillic
What does hydrophilic mean?
water soluble
What does hydrophobic mean?
not water soluble
What are non polar covalent bonds?
electrons are shared equally, shoes no poles
Are non polar covalent bonds hydrophilic or hydrophobic
hydrophobic
What are hydrogen bonds?
polar covalent bonds between hydrogen and other atoms
True or false: hydrogen bonds are stronger that covalent bonds
false: only 5% as strong as covalent bonds
How do hydrogen bonds form molecules?
they dont. cannot bind atoms into molecules, but can establish links between molecules
What are free radicles?
electrically charged atom or group of atoms with an unpaired electron in its valence electron shell
What makes free radicals unstable?
having an unpaired electron makes them unstable, highly reactive and destructive of nearby molecules
How are free radicals destructive?
either give up its unpaired electron or takes an electron from another nearby molecule, thus breaking the latter
What is a chemical reaction?
occurs when new bonds form between atoms or old bonds break between atoms within compounds, the foundation of all life processes
True or false: in a chemical reaction the total mass of reactants does not necessarily equal the total mass of the products
false: the total mass of the reactants equals the total mass of the products
Why do products and reactants of a chemical reactions have different chemical properties?
because of the rearrangement of the atoms
What is metabolism?
all chemical reactions occurring in the body
What is potential energy?
stored by matter
What is kinetic energy?
associated with matter in motion
What is chemical energy?
form of potential energy stored in bonds of compounds and molecules
What is the law of conservation of energy?
energy can be neither created or destroyed, the total amount of energy at beginning and end of a chemical reaction is the same, energy can only be transferred in a chemical reaction
Chemical reactions can be _________ or ___________
exergonic reactions or endergonic reactions
What are exergonic reactions?
release more energy than they abosrb
What are endergonic reactions?
absorb more energy than they release
How do exergonic and endergonic reactions interact with each other in metabolism?
coupled together
Give an example of exergonic reaction
breaking down glucose: some of the energy is released is stored in ATP (adenosine triphosphate), energy transferred to ATP is later used to drive endergonic reactions in process of building the body structure
What is activation energy?
energy needs to be invested to start a chemical reaction, reactants must absorb enough energy so they become unstable and their valence electrons can interact to form new combos
What factors influence the speed of chemical reactions?
concentration of reactants and temp of enviroment
What are catalysts, how are they used in the body?
lower of activation energy needed for a reaction to occur, normal temp and pressure within body are too low for most chemical reactions to occur fast enough to maintain life, so catalysts help witht hat
What is special about catalysts?
do not alter potential energy needed for reaction to occur, does not change at the end of reaction, can be used repeatedly, needed in small amount
What is the most important catalyst in the body?
enzymes
What is a synthesis reaction? give an example
two or more atoms, ions or molecules combine to form new and larger molecules, ie. simple aminoacids to form proteins
Are synthesis reactions usually endergonic or exergonic
endergonic
What are decomposition reactions? Give an example
catabolism larger molecules are split up into smaller atoms, ions or molecules ie breaking down glucose
are decomposition reactions usually exergonic or endergonic?
exergonic
What is an exchange reaction?
consist of both synthesis and decomposition reactions
What are reversible reactions
the products of a reaction can revert to original reactants when conditions of reaction change
What are oxidation reduction (redox) reactions?
oxidation and reduction, within cell redox reactions are coupled
What is oxidation?
loss of electrons from a molecule
What is reduction?
gain of electrons by a molecule
