DEFINITIONS SO FAR Flashcards
Atomic number
The number of protons in the nucleus of the atom
Mass (nucleon) number
The number of particles (protons and neutrons) in the nucleus
Isotopes
Atoms of the same element with the same number of neutrons but a different number of neutrons
Ions
An electrically charged particle formed by the loss or gain of one or more electrons from an atom or group of atoms
Relative isotopic mass
The mass of an atom of an isotope compared to 1/12th the mass of carbon 12
Relative atomic mass Ar
The weighted mean mass of an atom of an element compared to 1/12th the mass of carbon 12
Relative molecular mass Mr
The weighted mean mass of a molecule compared with 1/12th of the mass of an atom of carbon 12 (ONLY applies to simple covalent molecules e.g. O2 or CO2)
Relative formula mass
The weighted mean mass of a formula unit compared to 1/12th of the mass of an atom of carbon 12 (Can apply to ionic substances as they occur as giant lattices)
Molar gas volume
Volume per mole of gas.
Units= dm^3 mol^-1
At RTP= 24.0dm^3 mol^-1 approx.
Concentration (of a solution)
The amount of solute, in mol, dissolved per 1dm^3 (1000cm^3) of solution
Dilution
The process of decreasing the concentration of a solute in solution. Adding more solvent without adding more solute will reduce the concentration.
Compound
Atoms chemically joined
Molecule
2 or more atoms bonded with covalent bonds
Bond enthalpy
Average energy required to break one mole of that type of bond
Covalent bond
A shared pair of electrons
Ionic bond
Attraction (electrostatic) between oppositely charged ions
Element
Substance which contains only 1 type of atom
Orbital
A region that can be occupied by up to 2 electrons with opposite spins
Dative bond
Both of the shared electrons originate from the same species
Electronegativity
The ability of an atom to attract the bonding electrons in a covalent bond
Accuracy
How close to the true value a measurement is
Activation energy
Minimum energy required to start a reaction by breaking bonds in the reactants
Aim
The purpose of the investigation
Amount of substance
The quantity whose unit is mole. Amount of substance=counting atoms
Anhydrous
A substance containing no water molecules
Anion
Negatively charged ion
Anomalies
Data points that don’t fit the overall trend in the data
Anomalous
Results that don’t follow the general pattern of the data
Aqueous
A solution in which the solvent is water
Atom
Smallest object that retains properties of an element
Atomic structure
- Positively charged nucleus
- Negatively charged electrons in orbit
- Atom has 0 overall charge (equal no of protons and electrons)
Avogadro constant Na
Number of atoms per mole of the carbon 12 isotope (6.02*10^23)
Bond angle
Angle formed between two adjacent bonds on the same atom
Bonded pair
Pair of electrons that have been shared between two chemically bonded atoms
Bonding region
Space where an electron can be found in a bond
Catalyst
Substance which increases rate of reaction without being used up during the reaction
Cation
Positively charged ion😺
Chemical energy
Special form of potential energy stored in chemical bonds
Continuous variable
A measured value which could be any number
Control variable
A factor YOU MUST keep constant in experiments
D-orbital
A region (within an atom) which can hold up to 2 electrons with opposite spins
Dehydration
Chemical reaction where a water molecule is eliminated from an organic compound
Delocalised electrons
Electrons that are shared between more than 2 atoms
Delta
“A little bit”
Dependant variable
Factor you observe in the experiment
Diatomic molecules
Molecules composed ONLY of 2 atoms (can be the same or different elements)
Displacement reaction
A more reactive element takes the place of a less reactive element in the compound
Distillation
Technique used to separate miscible liquids or solutions
Dot and cross diagrams
Model the electrons in chemical bonding
Dot formulae
Ration between no. of compound molecules and the no. of water molecules within the crystalline structure
Electron
Smallest particle that makes up an atom, carry negative charge
Electron configuration
Arrangement of electrons in an atom or ion
Electron shielding
Repulsion between electrons in different inner shells. Shielding reduces the attraction between the positive nucleus and negatively charged outer shell electrons.
Empirical formula
Simplest whole no. ratio of atoms of each element in a compound
Giant covalent lattice
3D Structure of atoms, all bonded together by strong covalent bonds
Giant ionic lattice
3D Structure of oppositely charged ions, held together by strong electrostatic attraction between the oppositely charged ions
Giant metallic lattice
3D Structure of positive ions and delocalised electrons, bonded with strong metallic bonds
Group
Vertical column on periodic table
= No. of outer shell electrons
Same group=similar chemical properties
Hydrated
Crystalline compound containing water molecules
Hydration
Reaction where water is a reactant
Hydrocarbons
Compound containing ONLY hydrogen and carbon atoms
Hydrogen bond
Strong permanent dipole-dipole attraction between an electron deficient hydrogen atom on one molecule and a lone pair of electrons on a highly electronegative atom on a different molecule.
Hypothesis
Prediction + explanation of the chemistry behind the prediction
Incomplete combustion
Oxidising a fuel in a limited amount of air
Independent variable
The factor you change
Intermolecular force
Attractive force between neighbouring molecules or atoms
Ionisation
Process of an atom becoming an ion
Line of best fit
Shows trend of plotted points - could be a straight line, curve or S shape
London dispersion forces
Attractive forces between induced dipoles in neighbouring molecules
Lone pair
Outer shell pair of electrons not involved in chemical bonding
Margin of error
Shows the range which the value lies within
Metallic bonding
Electrostatic attraction between cations and delocalised electrons
Method
Step by step detailed explanation of how to complete an experiment
Molar mass M
Mass per mole of a substance
Units=g mol^-1
Molar volume
Volume per mole of gas
Units= dm^3 mol^-1
At RTP= 24.0 dm^3 mol^-1
Mole
Amount of substance containing as many particles as there are carbon atoms in exactly 12g of the carbon 12 isotope
Molecular formula
Shows no. and type of the atoms of each element in the compound
Neutron
Located in the nucleus of the atom
Mass=1
Charge=0
Nucleons
Protons and neutrons
P orbital
Region within the atom that can hold up to 2 electrons with opposite spins
Particle model
Simplified model of matter, used to explain observations and make predictions
Percentage yield
Actual amount, in mol, of product divided by theoretical amount, in mol, of product then times the answer by 100
Period
Horizontal rows of the periodic table
Elements show trends in properties across a period
Periodic table
Arrangement of chemical elements, organised by atomic number, electron configuration and recurring chemical properties
Periodicity
Regular periodic variation of properties of elements with atomic no. and position in the periodic table
Permanent dipole
Small charge difference across a bond due to differing electronegativities of the bonded atoms
Permanent dipole-dipole interaction
Weak attractive force between permanent dipoles and permanent dipoles or induced dipoles in neighbouring polar molecules
Polar covalent bond
Covalent bond which has a permanent dipole
Precipitation reaction
Formation of a solid during a reaction (often formed when 2 aqueous solutions are mixed together)
Precision
Degree to which repeated values (collected under the same conditions in the experiment) show the same result
Product
Substances made/formed in a chemical reaction
Proton
Found in nucleus
Has positive charge
Qualitative data
Description of what is being observed
Quantative data
Quantity (number) of what is being observed
Rate of reaction
Change in concentration of a reactant or product in a given time
Reactants
Substance that undergoes change in a reaction
Reliable
Results that are similar once repeated
S orbital
Spherical region, can hold up to 2 electrons with opposite spins
Scatter graphs
Method of expressing quantative data
Independent variable must be continuous and on x axis
Dependent variable must be continuous and on ten y axis
Separating funnel
Equipment used to separate immiscible liquids
Shell
Group of atomic orbitals with the same principal quantum number, n
Significant figures
Numbers used to represent a quantity that have a meaning
Degree of accuracy of answer
Single covalent bonds
Atoms bonded by one shared pair of electrons between nuclei
Simple molecular lattice
3D Structure of molecules held together by weak intermolecular forces
Species
Any type of particle that takes place in a chemical reaction
Standard form
Way of writing v small or v large numbers
A*10^n
A=value between 1 and 10
N=no of places and direction that the decimal point has been moved
Stock solution
The solution has a know concentration. Used commonly in titrations to work out unknown info about another substance
Sub shell
Group of the same type of atomic orbitals (s,p,d or f) within a shell. S= max 2 P= max 6 D= max 10 F= max 14
Valid experiment
Provides info to test the aim of the experiment
Variables
Factors that can affect the outcome of the experiment
Volume
Quantity of 3D space occupied by a solid, liquid or gas
Water of crystallisation
Water molecules that form an essential part of the crust structure of a compound
Yield
Amount of product obtained in a chemical reaction
Hydrocarbon
A compound containing only carbon and hydrogen
Saturated hydrocarbon
A hydrocarbon that only has single bonds
Unsaturated hydrocarbon
A hydrocarbon that has double or triple covalent bonds between adjacent carbon atoms. It must contain at least one carbon-to-carbon double bond
Aliphatic hydrocarbons
A hydrocarbon where carbon atoms are joined together in straight or branched chains
Alicyclic hydrocarbons
Hydrocarbons where carbon atoms are joined together in a ring structure
Functional group
A group of atoms that is responsible for the characteristic chemical reactions of a compound
Homologous series
A series of organic compounds that have the same functional group with successive members differing by CH2
