the chemistry of life Flashcards
what is matter?
the universe consists of matter which is moved around by energy.
matter occupies space and has a mass.
composed of elements
what are the 3 states of matter?
solid-definite shape and volume
liquid-definite volume , flows to fill space
gas-no defined shape or volume
what is energy?
energy is the ability to put matter into motion
capacity to do work
what is the difference between kinetic and potential energy?
kinetic - is that which moves things
potential- stored energy.when the energy is released it becomes kinetic energy.
what are some forms of energy?
chemical energy- stored in chemical bonds- ATP
electrical energy-movement of charged particles- nervous system
mechanical energy- energy directly involved in moving matter
radiant energy-energy that travels in waves
what are elements made of?
composed of atom.
what is the size of the smallest element?
smaller than 0.1nm
what is the size of largest element?
0.5nm
what are the 4 elements that make up 96.1% of our body?
C , O , H , N
how do elements differ from each other?
elements differ from each other by the number of protons, neutrons and electrons.
what is an isotope?
same number of electrons and protons but different number of neutrons.
each element has at least 2 isotopes.
what are molecules of an element?
when atoms of same element combine
e.g. H2 S8
what are molecules of a compound?
different kind of atoms combine.
e.g. H20
what are mixtures?
2+ components physically intermixed
what are the three types of mixture?
- solution
- colloids
- suspensions
what is the difference between compound and mixture?
.no chemical bond in mixture
.mixture can be separated physically via evaporation or filtering or straining
.compounds need chemical binds to be broken to separate
.compound is always homogenous
.mixture can be heterogenous or homogenous.
what are the three types of chemical bonds? and what do they do?
.ionic
.covalent
.hydrogen
they make sure that the atom is stable with 8 electrons in its valence shell
what does each electron shell represent?
each electron shell represents different energy level.
electrons therefore have potential energy
electron further away from nucleus has most potential energy.
what is ionic bonding?
two oppositely charged ions attract.
intermediate strength
what is covalent bonding?
electrons shared between two atoms. has the strongest bonding -single bond -double bond -triple bond
what are non polar molecules?
electrons are shared equally between both atoms
what are polar molecules?
electrons shared non equally between both atom
creation of dipole
what is electronegativity?
measure of electron sharing ability between atoms.
what are hydrogen bonds?
attraction between a H atom and an electronegative atom.
weakest bond.
what are chemical reactions?
these occur when electrons are gained or lost
it also occurs when chemical bonds are formed or rearranged or broken.
what are the 3 types of chemical reaction?
.synthesis-anabolic
.decomposition- catabolic
.displacement/exchange
what is a synthesis reactions?
smaller particles are bonded together to form larger more complex molecule.
e.g. amino acids joined to form a protein molecule.
A+B —> AB
what is a decomposition reaction?
large bonds are broken to form small particles.
e.g. glycogen broken down to form glucose.
AB —> A+B
what is a displacement reaction?
bonds are both made and broken
AB+C —>AC+B
what is a redox reaction?
oxidation and reduction state of atom is changed
what is oxidation?
loss of electron
what is reduction?
gain of electrons
what is exergonic?
chemical reaction that releases energy can be catabolic or oxidative.
what is endergonic?
chemical reaction that absorbs energy can be anabolic or reduction
what are the factors that influence chemical reaction rates?
.temperature
.concentration
.particle size
.catalysts
what bonds do all organic compounds have?
all organic compounds are covalently bonded.
what are the properties of water?
. high heat capacity . high heat of vaporisation . essential reactant in many reactions .universal solvent - due to being a dipole water is compressible
what are salts?
salts are ionic compounds.
when salts are dissolved in water , they dissociate into ions.
all ions are electrolytes in solution
e.g na and k have electrical properties in nerve impulse transmission and muscle contraction
what are acids?
acids release hydrogen ions when dissolved in water and anions
they are proton donors
they are also electrolytes
what are bases?
they dissociate in water and release hydroxide ions.
they bind to hydrogen ions.
bases can reduce the acidity of a solution by reducing hydrogen ions.
what is a ph scale?
acidity refers to free hydrogen ions in a solution.
what are buffers?
solution that minimises ph changes when a small amount of acid or base is added.
what organic compounds?
organic compounds contain carbon.
e.g. lipids , proteins , carbohydrates
how are organic compounds made?
made by dehydration process/ condensation
how are organic compounds broken?
they are broken by hydrolysis
What is radioactivity?
atomic delay
What is atomic delay?
mini-explosion from radioisoptopes
alpha particles
beta particles
gamma rays
What are radioisotopes?
unstable
dangerous
spontaneously decompose releasing energy such as alpha beta and gamma rays
What is a valence shell?
these electrons in the outermost energy level that take part in chemical bonding
