Unit 1: Chemical Changes and Structure Flashcards
What affects the Rate of Reaction?
Concentration
Particle Size
Temperature
Use of a Catalyst
How do you measure the rate of reaction?
Measuring:
- Changes in Mass(At Regular Time Intervals)
- Changes in Volume (At Regular Time Intervals)
- Changes inConcentration (At Regular Time Intervals)
What are reactions caused by?
Particles colliding with each other
Why does High Temperature affect Reaction Rate?
Particles have more energy and move quicker causing more frequent collisions with more energy
Why does Small Particle Size affect Reaction Rate?
Increased surface area means a higher chance of particles colliding
Why does High Concentration affect Reaction Rate?
More particles moving means more particle collisions
Calculating Rate of Reaction
Average Rate = Change in measurable Quantity/Change in Time
Units depend on measurable quantity and time
Reaction Graphs
Steeper Gradient = Faster Reaction
Flat/Straight line = End of Reaction
Atoms
Particles that make up everything. Made from protons, neutrons and electrons
Electrons
Negatively charged particles that orbit the nucleus. Their mass is so small it is nearly 0
Protons
Positively charged particles contained in the nucleus of the atom. Have a mass of 1amu
Neutrons
Particled with no charge that are also contained in the nucleus. Have a mass of 1amu
Nucleus
Centre of an atom made up from protons and neutrons. Has an overall positivie charge
Group 1
Alkali Metals. React rapidly with water, producing an alkaline solution and hydrogen gas
Group 0/8
Noble Gases. Very unreactive and exist as individual atoms
Atomic Number
How many protons an element has
Mass Number
Number of protons and neutrons in an atom
Isotopes
Atoms with the same atomic number but different mass numbers
Relative Atomic Mass (RAM)
Calclated from the masses of all the isotopes of an element taking into account the percentage proportion of each
Covalent Bond
A shared pair of electrons between two non-metal atoms
Diatomic Molecules
Bromine
Iodine
Chlorine
Fluorine
Oxygen
Hydrogen
Nitrogen
Linear Molecule
One shared electron
Bent Molecule
Two shared Electrons
Pyramidal Molecule
Three Shared Electrons
Tetrahedral Molecule
Four Shared Electrons
Ionic Bonding
Formed between a metal and a non-metal. An electrostatic force of attraction between a charged metal ion and an oppositely charged non-metal ion
Ionic Compunds
Easily Dissolve in water to form a conductive solution
Very high melting points
Don’t conduct when solid
Solid at room temperature
Covalent Network
Very high melting/boiling point
Solid at room temperature
Don’t conduct (except graphite)
Electrolysis
The breaking up of an ionic compund using electricity. Charged particles attracted to oppositely charged electrode where they lose/gain electrons to become neutral atoms/molecules
Prefixes
Mono - 1
Di - 2
Tri - 3
Tetra - 4
Penta - 5
Hexa - 6
Balanced Equations
When there are the same number of the type of every atom on both sides of the equation
Mass of One Mole
Gram Formula Mass (GFM)
Mole Calculations
Mass(g) = Number of Moles x Gram Formula Mass
m = n x GFM
Concentration Calculation
Number of Moles = Concentration (mol l-1) x Volume (l)
n=cv
Acids pH
Less than 7
Alkalis pH
More than 7
Neutral/Water pH
7
Formin Alkalis
Metal Oxide (base) dissolved in Water
Forming Acids
Non-Metal Oxide Dissolved in Water
When do Acids Occur?
When there are more H+ ions than OH- ions
When do Alkalis Occur?
There are more OH- ions than H+ ions
When do Neutral Solutions Occur?
There are an equal number of OH- ions and H+ ions
Dilution
Moving an acid or alkalis pH towards 7 with water.
Occurs as there is a lower concentration of ions as water is added
Neutralisation
Reaction of an acid with a base that results in the pH moving towards 7
Neutralisation Equations
Acid + Alkali → Salt + Water
Acid + Metal Oxide → Salt + Water
Neutralisation with Carbonates
H+ ion reacts with CO32- to form water and carbon dioxide
Metal Carbonate Neutralisation Equation
Metal Carbonate + Acid → Salt + Water + Carbon Dioxide
Carbon Dioxide Test
Tuns lime water milky/chalky white
Formation of Water
Hydrogen ion and Hydroxide ion combine to form water
H+(aq) + OH-(aq) → H2O(l)
Titration
Used to find the concentration of an Acid/Alkali
Base
Substance that reacts with an acid forming water