unit 1 Flashcards
Factors affecting rate of reaction
PARTICLE SIZE- increase in particle size=decrease in rate
CONCENTRATION- increase=more present particles=more likely collisions
TEMPERATURE- increase=particles more energy, move faster, more likely collisions
CATALYST USE- speed up reactions without being used up
Av Rate of Reaction Calculation
Δreactant/product ÷ Δtime
Periodic Groups
1=ALKALI METALS- very reactive metals
0=NOBLE GASES- unreactive
7=HALOGENS- very reactive non-metals
Nuclide Notation
MASS NO.- protons+neutrons
ATOMIC NO. - protons (also no. of electrons-atoms r neutral)
similar chemical properties
elements in same group have similar them properties as have same no. of outer electrons
Isotopes
Atoms which have SAME ATOMIC NO. but DIFFERENT MASS NO.
no. of NEUTRONS differs
Relative Atomic Mass
R.A.M of element = av mass element -Takes into account MASS of each isotope &PROPORTION of each isotope
R.A.M value- CLOSEST to MASS of most ABUNDANT isotope
Ions
ion is a charged particle formed by loss/gain of electrons
electron loss/gain diagram [ ]
What is the charge of ions depending on the group
Group 1 2 3 4 5 6 7 8
Charge + + 2 + 3 / 3- 2- - /
Ion-electron Equation (formation of ion)
S+ + 2e- → S2-
element - how much loss/ gain e - produces - Ion
Flame Testing
Flame test is analytical procedure used to detect presence of certain elements, primarily metal ions, based on color produced during test
many metal ions burn w coloured flames
How to test for element
- flame testing
- does element conduct
- what temp it melts/boils at
- H burns w squeaky pop, CO2 turns lime water cloudy
Bonding
- tranferring electrons - FORM IONS
2. share electrons - COVALENT BONDS
Ionic bonding
IONIC BONDS R ELECTROSTATIC FORCE OF ATTRACTION BETWEEN + AND - IONS
- metal bonds to nonmetal atom
- metal becomes +charge, nonmetal becomes -charge
- as 2 particles oppositely charged become attracted, form ionic bond
Ionic bonding diagram [ ]
what is the structure of Ionic Crystal Lattices [Ionic Compounds]
Ionic compounds form lattice structures of oppositely charged ions w each +ion surrounded by -ions, vice versa
ionic bonds r so strong- ions r fixed together unable to move
Formula of ionic Compound
tells Ratio of ions in lattice, not actual no. of ions present:
Ca : F ratio: 1 : 2
formula: CaF₂
Covalent bonding
FORCES OF ATTRACTION MADE BY NONMETAL ATOMS SHARING OUTER ELECTRONS. molecule is group atoms held together by covalent bonds.
Bonding(e sharing) diagram
What holds atoms together?
NUCLEI of atoms have MUTUAL ATTRACTIONS FOR SHARED PAIR OF ELECTRONS.
this holds atoms together in covalent bonds
what are Diatomic elements and name them
diatomic molecule only has 2 atoms
H2, N2, I2, Br2, F2, O2, Cl2
Shapes of Molecules
- LINEAR
- ANGULAR
- TRIGONAL PYRAMIDAL
- TETRAHEDRAL
Covalent Network Structures
billions atoms in one crystal joined together as one giant molecule- network structure e.g. carbon in form of graphite/diamond, silica(sand)
covalent substances can either form discrete(small molecule) molecular subs/giant network structures
Metallic Bonding
Metallic bonding is ELECTROSTATIC FORCE OF ATTRACTION BETWEEN POSITIVELY CHARGED IONS AND DELOCALISED ELECTRONS
how are Metallic Structures made
consists of one giant lattice of +charged ions in sea of delocalised outer electrons.- free to move.
Melting and Boiling Point of Covalent Molecular Structures
To move molecules apart forces of attraction between molecules must be broken
C.M.S. FORCES R WEAK- tend to have LOW MELTING & BOILING POINTS
as result most r GASES/LIQUIDS at room temp
Melting and Boiling Points of Covalent Network Structures
MELTING involves BREAKING STRONG COVALENT BONDS within networks
REQUIRES LOT OF ENERGY- MELTING & BOILING POINTS R HIGH
Melting and Boiling Points of Ionic Substances
MELTING involves BREAKING STRONG IONIC BONDS between ions in lattice
REQUIRES LOT OF ENERGY- HIGH MELTING & BOILING POINTS
Solubility of ionic substances in water and do covalent substances dissolve in water
WATER GOOD for many IONIC SUBS. [ LATTICE BREAKS UP COMPLETELY TO LEAVE MANY FREE IONS IN SOLUTION ]
MOST COVALENT SUBS DONT DISOLVE IN WATER BUT CAN IN OTHER SOLVENTS
Conductivity in Elements
might need diagram
- METAL elements CONDUCT
- NONMETAL DONT- exception is CARBON in form GRAPHITE
Conductivity in Compounds
might need diagram
- COVALENT SUBS DONT CONDUCT in any state
- IONIC SUBS CANT CONDUCT SOLID, CAN IN SOLUTION/MOLTEN
Electricity
a flow of charged particles
Conductivity in Metallic Bonding
all metals can conduct as delocalised electrons are free to move
Conductivity in Covalent Bonding
Covalent subs don’t conduction any state as there’s no charged particles free to move
Conductivity in Ionic Bonding
solid- don’t conduct as ions held tight in lattice and aren’t free to move
dissolved in water/molten- ionic lattice breaks up completely and ions free to move
electrolysis
an ionic solution or melt which conducts electricity-called an ELECTROLYTE
Process of passing current through electrolyte- ELECTROLYSIS
ELECTROLYSIS= splitting compound into constituent elements. D.C. power supply used to identify products
what happens during Electrolysis
might need diagram
During electrolysis:
+METAL IONS attracted to -ELECTRODE where they GAIN electrons
-NONMETAL IONS attracted to +ELECTRODE where they LOSE electrons
Formula for Compounds
ide- contain 2 elements
ite/ate- oxygen is present
Valency
Combining power of element is no. of single bonds it can make
Group 1 2 3 4 5 6 7 8
valency 1 2 3 4 3 2 1 0
formula mass calculations
m n gfm
calculations based equations
in question mentions 2 subs
needs balanced equation
use molar ratio
m n gfm & n c v
n=cv units
c=mol/l or mol l-1
v= litres (remember to CONVERT if in CM3)
n=moles
What is a Solution
SOLUTION when SOLUTE(SOLID) dissolves in SOLVENT(LIQUID)
Standard Solutions
A SOLUTION whose CONCENTRATION is ACCURATELY KNOWN
cld have to do molar ratio qs
How to Make Standard Solution
- CORRECT MASS OF SUBSTANCE ACCURATELY MEASURED (beaker/weighing boat)
- ALL SUCCESSFULY TRANSFERRED TO VOLUMETRIC FLASK
- TAKE A RINSING of whatever was used to measure substance
- KEEP ADDING WATER TO FLASK TILL BOTTOM OF MENISCUS TOUCHES THE MARK
What is pH scale indication of
the hydrogen ion concentration of a solution
why is water neutral
-DISASSOCIATES into equal concentration of H+and OH- ions
-REVERSIBLE REACTION
only small amount disassociate
Acid solution formula of: Hydrochloric acid nitric acid Sulphuric acid Ethnoic acid
HCL
HNO3
H2SO4
CH3COOH
Alkali solution formula of: Sodium hydroxide Potassium hydroxide Calcium hydroxide Ammonia
NaOH
KOH
Ca(OH)2
NH3
What happens to acid/alkali when diluted
pH no. moves toward 7
how to make Alkali solution
METAL OXIDES & HYDROXIDES DISSOLVED IN WATER = ALKALINE SOLUTION
Ammonia gas dissolved in water= alkali
how to make an acid
NON METAL OXIDES DISSOLVED IN WATER= ACIDIC SOLUTION
what affect do insoluble substances have on pH of water
insoluble subs do not affect pH of water
What is a Base
BASE= substance which NEUTRALISES ACID
BASES= METAL OXIDES, METAL HYDROXIDES, METAL CARBONATES
Alkalis r bases that dissolve in water(soluble bases)
What is Neutralisation
- REACTION of ACID W ALKALI
- Produces SALT & WATER
- When base is METAL CARBONATE CO2 formed too
What are Volumetric Titrations
Technique that allows EXACT ACID VOLUME NEEDED to NEUTRALISE ALKALI to be CALCULATED
How to do Titration
- burette filled w acid up to 0 mark
- u know ACID CONC but not of ALKALI
- KNOWN V of ALKALI put in conical flask-contains INDICATOR
- acid carefully let into flask
- when ALKALI NEUTRALISED, indictor changes colour, stop acid flow= ENDPOINT
For how long is Titration Repeated Till
till 2 CONCORDANT(lie within .2cm3) RESULTS OBTAINED
How do you do a volumetric titration calculation
- Rough titration ignored
- calc av of concordant results (Volume)
- do molar ratio equation calc using n,c,v
What is a precipitation reaction
when 2 SOLUTIONS REACT TO FORM A SOLID (called PRECIPITATE)
SOLID CAN BE COLLECTED BY FILTRATION
How can a Precipitation Reaction be Easily Identified
by the formation of a Solid product from Aqueous Reactants
How do you do Ionic Equations
Precipitation reactions-making insoluble salts
- write out BALANCED EQUATION W STATE SYMBOLS
- SPLIT ionic compounds writing in individual CHARGES & any small no.’s outside brackets make them big in front. Remove state symbols
- in same line SCORE OUT SPECTATOR IONS
- write out what’s left of ionic equation
What are Spectator Ions
ions which remain UNCHANGED by reaction as they DONT TAKE PART in REACTION
Drawing Line Graph tips
important
- unlike in biology always FREEHAND graphs
- line/curve is for GENERAL TREND
- LINE DOESNT NEED TO PASS EVERY POINT; outlier/error
- for curved line freehand, doesn’t need to pass each point
- for straight line use ruler, doest need to pass each point
