Chemistry Test On Everything Flashcards
What does EXOTHERMIC reactions mean
Temperature increase
What does endothermic reactions mean
Temperature decrease
What’s neutralisation include
Formation of a salt
What does effervescence reactions include
Gas been given off
Can a physical change and a chemical change be reversed
A physical change can be reversed but a chemical change can not be reversed
What are examples of a physical change
Boiling water Melting ice Diluting juice with water Breaking glass Filtering sand from water Separating alcohol from water by distilling
What are the signs of a chemical reaction
Colour change
Change in energy
What are the examples of a chemical reaction
Frying an egg
Toasting bread
Rust on a car
Adding sodium to water
What is a mixture
A mixture is when two or more substances are mixed together but have not actually joined together and reacted mixtures can usually be separated easily
How do compounds form
Compounds are formed when elements react together. Compounds can have different properties to the elements that make them up
Are compounds easy or hard to separate
Compounds are hard to separate into their elements
What does ‘ide’ mean in elements
If a compound has ide, it contains two types of elements
E.g. Sodium chloride - NaCl
Iron oxide - FeO
What does ‘ite’ and ‘ate’ mean in elements
If a compound ends in ‘ite’ and ‘ate’, it contains two types of element plus it also contains oxygen
E.g. Sodium chlorate - Sodium chlorine oxygen
Iron sulphate - iron sulphur oxygen
What’s a physical change
Substances may seem different, but the way the atoms link up is the same. It changes shape or size. It dissolves. It changes phase (freezes,boils,evaporation,condenses)
What is a chemical change
Changes the way the atoms link up. Makes new substances. Change in colour. Temperature change (increases or decrease). Gas given off (effervent). Formation of a solid
What are compounds
Compounds are formed when two or more elements chemically join together (bonded). The different types of atoms becomes together.
What is a mixture
Mixtures are formed when two or more different substances come together but without chemically joining. These different substances may be elements or compounds
What does exothermic mean
Heat energy given out (exit) to its surrounding (temperature increase)
What does endothermic mean
Heat energy taken it (enter) the reaction from the surroundings (temperature decrease)
What does diatomic mean
Only contains 2 atoms
What does solute mean
Solid part if the solution
What does solution mean
The combined solvent and solute
What does solvent mean
Liquid part of the solution e.g. Water
What does Saturated soluction mean
A solution where no more solute can dissolve
What does Aquaus mean
When something has dissolved in water e.g. salt water
What are Distillations
Technique used to separate a mixture of liquid using their boiling points
What is alloy
A compound of metals
What is filteration
Separation Technique used for separating a liquid and a solid
What are reactants
These are chemicals that are reacting with each other
What’s an independent variable
What is being changed
What’s an dependant variable
What you are measuring (depends if the independent or changes as a result of independence)
What are control variables
Things you keep the same so you can figure what is different
E.g. Magnesium. Copper. Zinc
0.1 acid. 0.1 acid. 0.1 acid
Mass of. Mass of Mass of
Metal Metal. Metal
You keep everything the same but change the metal
What is a fair test
Changing one thing, keeping everything else the same
What are enzymes
Enzymes are biological catalysts. They help the reactions that occur in our bodies by controlling the rate of reaction.
What is denature
Changes shape so it decrease reaction rate
What are catalysts
Substances which speed up a chemical reaction without being used up (they can be recovered)
What is activation energy
Energy required to start a reaction
What is homogenous catalyst
A catalyst in the same state as the reactions
What is a heterogenous catalyst
A catalyst in a different state as the reactants
What’s an isotope
An element which has the same protons but different neutrons
What are ions
Charged particles
What is a molecule
Two or more atoms held together by covalent bonds
What is a covalent bond
Bond between non-metals where pairs of electrons are shared
What is a ionic formulae
The ionic formula of a compound shows the charges on the ions
What is electricity
Electricity is a flow of charged particles
What are atoms
The smaller part of an element that can exist. (electron,proton,neutrons make up an atom)
What are some key definitions for soluble,solution,solvent
If something is soluble you can dissolve it to make a solution. The substance that gets dissolved is called the solute. The substance that does the dissolving is called the solvent. If something is insoluble it cannot be dissolved by the solvent
What are the states of matter
Solid - S
Liquid - L
Gas - G
Aqueaus - AQ
What are some important notes on atoms
All atoms are very small particles. All the atoms in an elements are the same. Atoms make up of subatomic particles.
3 main ones - PROTON
- NEUTRON
- ELECTRON
What are my notes on chemical reactions
Before a chemical reaction can take place, the particles of the reacting chemicals must collide. With a solid, only the particles on the outside can come together and react. So the larger the surface area the faster the reaction. Smaller particles means bigger surface area and so a faster rate of reactions. Larger particles means smaller surface area and a slower rate of reaction.
How can you measure the rate of reactions
You can measure the rate of reaction by the mass lost. Volume of gas or temperature.
What is activation energy
For the reaction to happen the particles must have a certain amount of energy - this is called activation energy
What are the 5 things that a reaction depends on
1) temperature of the reactants
2) their concentration
3) their surface area
4) if a gaseous reaction - the pressure
5) whether or not a catalyst is used
How can you speed up a reaction
By heating the particles - this gives them more energy
How can you measure 1.volume of gas vs time
2. Loss of mass vs time
3. Change in concentration
4. Average rates and 5. 6.
- Rate = change in volume/time. 6. Volume cm3/time sec.
- Rate = change in mass/time
- Rate = change in concentration/time
- Rate = change in measured quality/change in time
- Rate = mass g/time mins
What is the charge of protons,electrons and neutrons, where is it found and what is its mass
Proton - + - nucleus - 1
Electrons = - = orbiting the nucleus = 0 (or 1/17 43)
Neutrons - 0 - nucleus - 1
What are the laws and rules of the periodic table
The atomic number must be smaller than the atomic mass. Protons and electrons will always be positive and negative. Electrons must add up to the same amount of protons. The amount of protons and neutrons are double the amount of electrons. No one type of atom has the same no. Protons and neutrons as another. Atomic mass=p+n
What are isotopes
Isotopes are atoms of the same element with different mass numbers
That is;
Same atomic no.
Same no. of P
Different mass number
Different no. of N
What are the isotope examples of Hydrogen
Protium. P-1 N-0 E-1 = used for hardening margarine
Deuterium P-1 N-1 E-1 = used in heavy or deuterated water solvent
Tritium P-1 N-2 E-1 = radioactive, used in H-bombs, glow in dark paints
Notes on chemical bonding
So the most stable,most unreactive have full outer shells/energy levels. By gaining the same electron arrangement as noble gases.
How do you form ions
For atoms to become ions they can either add electrons or loose electrons. To become stable s full outer energy level is needed.
What are the 3 different types of bonding
Ionic binding=metal + non-metal (involves ions) (loose or gain electrons)
Metallic bonding=metal+metal (share electrons)
Covalent bonding=non-metals + non-metals (share electrons)
What is a chemical formula.
A chemical formula gives the number of atoms of each element in a molecule of a colvent substance or ionic unit. Made up of symbol + numbers
What are the steps for writing the chemical formula
- Write elements symbols MgO
- Write the valency at the top right hand side of each element Mg2O2
- Cross over the valencies
- Check if you can simplify the formula MgO
What are the prefixes
Mono or mon =1. Hexa =6 Di =2 Tri =3 Tetra =4 Penta =5
What does it mean that opposites attract
The positively charged nuclei are both attracted by the shared pair of electrons
What is ionic bonding
An ionic bond is frowned between a metal + non-metal
How do you do the ionic compound formula.
The formula of an ionic compound is found using the valency method as covalent bonding
Valency -> cross -> divide (even if it’s y1)
What are the symbols you use for 3D nature of molecules
Triangle - in front
Full line - sample place
Dotted line - behind
What are the lines for VSEPR
2 bonds - linear or bent
3 bonds - pyramidal
4 bonds - tetrahedral
What are the valencies for the groups in the periodic table metals
Group 1 ,1 outer electron, loses 1 electron X+
Group 2, 2 outer electrons, loses 2 electrons X2+
Group 3, 3 outer electrons, loses 3 electrons X3+
What are the valencies for the groups in the periodic table non-metals
Group 5, 5 outer electrons, gains 3 electrons
Group 6, 6 outer electrons, gains 2 electrons
Group 7, 7 outer electrons, gains 1 electron
What are the rules for the ionic formula
- Symbols
- Write the ion charges
- Balance the charges
- Write the ionic formulae with brackets
What’s the name for when electrons are free to move
This is called delocalised
What does electro and lysis mean
Electro. Lysis
⬇️. ⬇️
Using Break
Electricity Apart
Why don’t non metals conduct
Non metals have no free electrons do they can’t move, so they can’t conduct electricity
Do covalent, solid ionic compounds, aqueous ionic compounds and molten ionic compounds conduct electricity
Covalent compounds➡️don’t conduct➡️no charged particles
Solid ionic compounds➡️don’t conduct➡️ions can’t move
Aqueous ionic compounds➡️do conduct➡️form ions
Molten ionic compounds➡️do conduct➡️ions free to move
What are the colours of the ions
Yellow Orange Green Colourless Purple Blue
What element is represented by yellow
Chromate - negative ion
Sodium chromate
Potassium chromate
What element is represented by orange
Dichromate = negative ion
Potassium dichromate
Sodium dichromate
What element is represented by green
Nickel = positive ion
Nickel nitrate
Nickel sulphate
What element is represented by colourless
Sodium chloride
Sodium nitrate
Potassium sulphate
What element is represented by purple
Permanganate = negative ion
Potassium permanganate
What element is represented by blue
Copper = positive ion
Copper nitrate
Copper sulphate
Copper chloride
What happens to the ions during ion migration
Positive ions. ➡️ negative electrode
(Metals/groups)
Negative ions. ➡️ positive electrode
Non-metals/groups)
Is water ionic
Yes, but sometimes dissolves in ionic things
What are the structure of ionic compounds
Ionic compounds have a particular structure (lattice). There are TWO types of covalent structures. Ions in a solid state cannot move, hence no conduction
Describe ionic
Solid at room temperature. High melting and boiling points due to STRONG attraction between ions. Conduct electricity when molten or in solution, but NOT solid
What’s the structure of covalent compounds (covalent discrete molecules)
Small molecules of a few atoms bonded together (e.g. H2O, CO2, CH4). Gas or liquid at room temperature. Low melting and boiling points due to WEAK attraction between molecules
What’s the structure of covalent compounds (covalent networks)
Large networks of thousands of atoms bonded together e.g. graphite, diamond, SiO2 (sand). Solid at room temperature. High melting and boiling points due to STRONG covalent bonding between all atoms. Do NOT conduct electricity in any state (except graphite)
Does covalent networks conduct electricity
Do not conduct electricity
Does ionic lattice conduct electricity
Do conduct electricity when liquid but not solid
Does metallic lattice conduct electricity
Conduct electricity when solid and have a wide range of melting points
Does discrete covalent molecular conduct electricity
Does not conduct electricity
What is a valency
The number of bonds an atoms can form (depends on group from periodic table)
What are the rules for the chemical formula
- Write symbols of elements present in compound
- Put valency above each symbol
- Cross valency over (swap and drop)
- Cancel down ratio if necessary
- Write correct chemical formula
What are the Roman numerals
I - 1. VI - 6 II - 2 III- 3 IV- 4 V - 5
Why are Roman numerals used
Some elements, particularly the transition metals in the centre block of the periodic table can have more the one valency. Roman numerals are often used to show the valency for these elements e.g. Cu
What are the rules for balancing equations
- Work out the number of atoms of each element on both sides of the reaction
- Pick an element which doesn’t balance and pencil in a number in front to make it balance
- Recount your atoms
- If your atoms still don’t balance repeat until everything balances
What is the moles and GFM
In chemistry the mole is the gram formula mass (GFM) or relative atomic mass (RAM) of a substance. This is really the same as the formula mass, but with grams as the unit
How do you do mole calculations
Number of moles = mass in grams ➗ mass of 1 mole
Mass (g) = number of moles ✖️mass of 1 mole
Mass of mole = mass in grams ➗ number of moles
How do you do solution calculations
Number of moles (mol) = concentration ✖️ volume
Concentration (moll-1) = no. of moles ➗ volume
Volume (l) = no. of moles ➗ concentration
Are ions present in acid and alkali solutions
Ions are present in acid and alkali solutions
Why does water not conduct electricity
Water has a low concentration of ions. Hence acids and alkalis are far better conductors than water
Explain what’s in a neutral solution
In neutral solutions such as water, the concentration of hydrogen ions H+ (AQ) and hydroxide ions OH- (AQ) is equal
What do acids and alkalis make more of in each
Acids make more H+ ions in solution
Bases make more OH- ions in solution
Water contains exactly the same number of H+ and OH-
What is neutralisation
Neutralisation is the reaction of an acid with a neutralised. Any substance which neutralises an acid is known as a base. Bases which dissolve in water are known as alkalis
What are the 4 important reactions of acids
Acid ➕ alkali ➡️ salt and water
Acid ➕ metal oxide ➡️ salt and water
Acid ➕ metal carbonate ➡️ salt ➕ water ➕ carbon dioxide
Acid ➕ metal ➡️ sodium chloride (salt) ➕ hydrogen
Why do we use titration
A bursts is an accurate way to measure the volume of a liquid as you run it into a container. In a titration we can measure exactly how much acid is needed to neutralise certain volume of alkali
What is titration used for
Titration is used to find the exact concentration of a solution. Usually an acid or alkali. We measure the exact volume needed to react. Using the balanced equation for the reaction we can work out how many moles we must have. Then we use the formula conc. - moles/volume
What are the titration calculations
- (Alkali) pvc= pvc (acid)
- nAlkali ✖️ c ✖️ v = nAcid ✖️ c ✖️ v
- C1 ✖️ V1 ➗ N1 = C1 ✖️ V1 ➗ N1
What is the ionic equation
These are different to normal formula equations.
- Write out the normal formula equation first
- Any compounds that are ionic - show them as ions in which state (g,l,s)
- Remove any SPECTATOR IONS
What does spectator ions mean
An ion that is press as both a reactant and a product in a chemical equation, spectator ions take NO PART in the reaction.
What are reactants
These are the chemicals that are reacting with each other
What happens when they react
Some changes may occur
What are products
These are the new substances formed after the reaction
What does molten mean
It described a liquid formed by melting a solid
What is pH
A measure of how acidic or alkaline a substance is
