chemistry glossary Flashcards
concentration
amount of substance given in a defined space
another definition could be the amount of solute dissolved in a solvent
calculations: C = n/V
Concentration = moles / volume
pressure
the force/area
pressure is defined as the physical force exerted on an object
pressure (gas)
Gas pressure is the name given to the force exerted by gas particles COLLIDING with the wall of their container
volume (gas)
The volume of gas is defined as the space occupied by the gaseous particles at standard temperature and pressure conditions
gas laws (year 11 revision)
laws that relate the pressure, volume, and temperature of a gas
what are the five gas laws?
-Boyle’s law
-Gay-Lussac’s law
-Avogadro’s law
-Charles’s Law
-The Combined Gas Law (or ideal gas laws)
what does boyle’s law state?
so the boyle’s law describes the relationship between the volume and pressure of gases AT constant temperature
“the volume of a gas is inversely proportional to the pressure of a gas at a constant temperature”
boyle’s law equations
hint: pressure and volume
can be written as
V ∝ 1/P or P ∝ 1/V or PV = k1
can be used to determine the current pressure or volume of gas and can be represented also as;
P1V1 = P2V2
charles’ law
hint: volume and temperature
in a closed system, charle’s law states that at constant pressure, the volume of a gas is directly proportional to the temperature (especially measured in kelvins)
this particular law describes the relationship between the temperature and volume of the gas
charles’ law equations
V ∝ T (volume inversely proportional to temperature)
Where, V = volume of gas, T = temperature of the gas in Kelvin. Another form of this equation can be written as;
V1 / T1 = V2 / T2
gay lussc’s law
hint: temperature and pressure
Gay-Lussac law gives the relationship between temperature and pressure at constant volume
at a constant volume, the pressure of the gas is directly proportional to the temperature for a given gas
gay lussc’s law equations
P ∝ T or P / T = k1
P1 / T1 = P2 / T2
Where P is the pressure of the gas and T is the temperature of the gas in Kelvin.
Avogadro’s law
Avogadro’s law states that if the gas is an ideal gas
(An ideal gas is defined as one for which both the volume of molecules and forces between the molecules are so small that they have no effect on the behavior of the gas),
the same number of molecules exists in the system
“The law also states that if the volume of gases is equal it means that the number of the molecule will be the same as the ideal gas only when it has equal volume”
Avogadro’s law equations
V / n = constant
or
V1 / n1 = V2 / n2
Where V is the volume of an ideal gas and n in the above equation represent the number of gas molecules
combined gas laws
The combined gas law is also known as a general gas equation is obtained by combining three gas laws which include Charle’s law, Boyle’s Law and Gay-Lussac law
the relationship between pressure, volume and temperature is for a fixed quantity of gas
combined gas laws equations
The general equation of combined gas law is given as;
PV / T = k
If we want to compare the same gas in different cases, the law can be represented as;
P1V1 / T1 = P2V2 / T2
Ideal Gas Law
the ideal gas law is also an amalgamation of four different gas laws. Here, Avogadro’s law is added and the combined gas law is converted into the ideal gas law
This law relates four different variables which are pressure, volume, no of moles or molecules and temperature
Ideal Gas Law equations
Mathematically Ideal gas law is expressed as;
PV=nRT
Where,
V = volume of gas.
T = temperature of the gas.
P = pressure of the gas.
R = universal gas constant.
n denotes the number of moles.
what happens to the volume when temperature is increased
the volume increases as the temperature increases
moles
the mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance
Calculations:
n=M/m
moles = molar mass / mass
molar mass can be found in the periodic table***
electronegativity
Electronegativity is a measure of an atom’s ability to attract shared electrons to itself
electronegativity generally increases as you move from left to right across a period
decreases as you move down a group
ionization energy
the amount of energy required to remove an electron from an isolated atom or molecule
ionisation energy decreases down a group, and increases from left to right across a period
electron affinity
the energy change that occurs as an atom gains electrons
Electron affinity increases across the periodic table from left to right due to nuclear charge increases.
It also increases from bottom to top in the periodic table due to atomic size
atomic radius
The atomic radius of a chemical element is a measure of the size of its atom
also means distance from the center of the nucleus to the outermost isolated electron (atomic size)
the atomic radius of atoms generally decreases from left to right across a period
The atomic radius of atoms generally increases from top to bottom within a group
melting point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid
Thus, higher the stronger the bond between the atoms, the higher will be the melting poin
isotopes
Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons
e.g hydrogen-1 and hydrogen-2 (deuterium)
Examples of radioactive isotopes include carbon-14, tritium (hydrogen-3), chlorine-36, uranium-235, and uranium-238.
diluted
weakened or thinned by or as if by having been mixed with something else (such as water)
vigour
characterized by or involving physical strength, effort, or energy
covalent bond
Covalent bonding involves the sharing of electrons between two or more atoms
e.g water (H2O), carbon dioxide
Ionic bonds
Ionic bonds form when two or more ions come together and are held together by charge differences.
standard solutions
Standard solutions are solutions of accurately known concentrations, prepared using standard substance
