Unit 1 Flashcards
Homogenous mixture
- Uniform and evenly distributed structure of composition
- Components not separated or distinguished
Heterogenous mixture
- Distinct substances without uniform composition
- Components remain separate from each other
Reaction of metal and water
Metal + Water -> Metal Hydroxide + H2
Reaction of Metal and acid
Metal + Acid -> Salt + H2
Reaction of Metal oxide and water
Metal Oxide + Water -> Metal hydroxide
Reaction of Metal oxide and acid
Metal oxide + Acid -> Salt + Water
Decomposition of carbonic acid
Carbonic Acid -> Water + Carbon Dioxide
Thermal decomposition of metal carbonate
Metal Carbonate -> CO2 + Metal Oxide
Thermal decomposition of Metal bicarbonate
Metal Bicarbonate -> H2O + CO2 + Metal Carbonate
Reaction of Metal Carbonate and Acid
Metal Carbonate + Acid -> Salt + H2O + CO2
Reaction of Metal Bicarbonate and Acid
Metal Bicarbonate + Acid -> Salt + H2O + CO2
Titration steps
1) Measuring a known volume of one of the solutions and placing into conical flask
2) Other solution placed in burette
3) A few drops of the indicator are added
4) The tap on the burette is carefully opened and the solution added to the conical flask until the indicator just changes colour
5) Multiple trials are carried out until concordant results are obtained
Back titration purpose
To find % purity of a substance from impure material using titration
Given:
- Mass of a substance
- Initial volume and concentration of analyte
Back titration steps
1) Initial volume of Analyte = Concentration * Volume of Analyte
2) Titrate remaining moles of analyte, after reacting with impure substance
3) Moles of analyte reacted with the impure substance (Initial mole of analyte - Remaining mole of analyte)
4) Moles of substance in impure material, reacted with the titrant = mole of analyte reacted * mole ratio between analyte and substance
Limiting / Excess Reactant
Limiting: Reactant used up first and determines amount of product produced
Excess: A reactant that remains after reaction is finished
Conditions of ideal gases
- No interaction between gas particles
- Ideal gases are point particles (no volume)
- No energy loss after ideal gases collide with each other
- Real gases show ideal behavior at low pressure, high temp
Avogadro’s law
Under same temperature and pressure, volume of gas is proportional to the moles
Elements
substances made from one kind of atom, they take part in chemical reactions in which new substances are made in processes that most often involve an energy change
Compounds
made from two or more elements chemically combined, atoms combine together in fixed ratios that will give them full outer shells of electrons, producing compounds
Mixtures
elements and compounds are interspersed with each other, but are not chemically combined. Components of a mixture retain the same characteristic properties as when they are in their pure form
Solvation / Filtration
Used to separate an undissolved solid from a mixture of the solid and a liquid / solution
1) Filter paper is placed in a filter funnel above another beaker
2) The mixture of insoluble solid and liquid is poured into the filter funnel
3) Filter paper will only allow small liquid particles to pass through in the filtrate
4) Solid particles are too large to pass through the filter paper so will stay behind as a residue
Crystallization
Used to separate a dissolved solid from a solution
1) The solution is heated, allowing the solvent to evaporate and leaving a saturated solution behind
2) You can test if the solution is saturated by dipping a clean, dry, cold glass rod into the solution. If saturated, crystals will form on glass rod
3) allowed to cool slowly and solids will come out of the solution as the solubility decreases, and crystals will grow
4) Crystals are collected by filtering the solution
5) Washed with distilled water to remove any impurities
Recrystalization
used to purify impure solids
1) hot solvent is used to dissolve both the organic solid and the impurities and then as the solution cools the solid crystallizes out and leaves behind the impurities in the solution
2) minimum amount of solvent to dissolve the solid and avoid loss of the product
3) If any solid impurities remain in the solution, a hot filtration can be carried out
4) once the solution has cooled down to room temperature and crystallised then the product crystals can be recovered by filtration
Simple Distillation
Used to separate a liquid and soluble solid from a solution
1) The solution is heated and pure water evaporates producing a vapour which rises through the neck of the round-bottomed flask
2) The vapour passes through the condenser, where it cools and condenses, turning into pure water which is collected in a beaker
3) After all the water is evaporated from the solution, only the solid solute will be left behind
Fractional Distillation
Used to separate two or more liquids that are miscible with one another
1) solution is heated to the temperature of the substance with the lowest boiling point
2) substance will rise and evaporate first, and vapours will pass through a condenser, where they cool and condense, turning into a liquid that will be collected in a beaker
3) All of the substance is evaporated and collected, leaving behind the other components(s) of the mixture
Paper Chromatography
Used to separate substances that have different solubilities in a given solvent
1) pencil line is drawn on chromatography paper and spots of the sample are placed on it. Pencil is used for this as ink would run into the chromatogram along with the samples
2) paper is then lowered into the solvent container, making sure that the pencil line sits above the level of the solvent so the samples dont wash into the solvent container
3) The solvent travels up the paper by capillary action, taking some of the coloured substances with it
4) This will show the different components of the ink / dye
Retardation Factor Formula
Distance travelled by component / distance travelled by solvent
Retardation Factor
The Rf value is used to quantify the distance a particular component travels relative to the solvent front
Rf values for compounds are calculated using measurements from the paper chromatogram or TLC
Solid / liquid / gas Particle Arrangement
High Density / Medium Density/ Low Density
Regular pattern of arrangement for particles / Random arrangement for particles / Random arrangement for particles
Vibrate around fixed positon / Move around each other / Move quickly in all directions
Low energy / Greater Energy / Greatest Energy
Solid to Gas
Gas to Solid
Sublimation
Deposition
Avogadro’s Constnat
The number of particles equivalent to the relative atomic mass or molecular mass of a substance in grams. Value: 6.02*10^23 / mol
Mass of substance with this number of particles called molar mass
Particles formula
Moles x Avogadro’s Constant
Concentration
Concentration of a solution is the amount of solute dissolved in a solvent to make 1 dm3 of solution
Concentration (moles) formula
Number of moles of solute / Volume of solution
Concentration (mass) formula
Mass of solute / Volume of solute
Parts per million
1 ppm is defined as A mass of 1 mg dissolved in 1 dm3 of water. Used when expressing extremely low concentrations of units.
Limitations of ideal gas laws
Gases do not fit this description exactly but may come very close and are called real gases
Boyle’s Law
P1V1=P2V2
Charles’ Law
V1/T1=V2/T2
Gay Lucacc’s Law
P1/T1=P2/T2
Combined Gas laws
P1T1/V1=P2T2/V2
Ideal Gas laws
PV=nRT
Number of moles formula
Mass of substance / Molar Mass
Volume of gas formula
Amount of Gas (mol) x 22.7dm^3/mol
Volumetric analysis (Titration)
process that uses the volume and concentration of one chemical reactant to determine the concentration of another unknown solution
How to determine limiting and excess reactants?
find the moles of each substance and divide the moles by the coefficient in the equation. The lowest number resulting is the limiting reactant
Why do not all reactants form products?
Other reactions take place simultaneously
The reaction does not go to completion
Products are lost during separation and purification
Percentage yield formula
Actual Yield / Theoretical Yield * 100
Actual vs theoretical yield
the number of moles or mass of product obtained experimentally vs number of moles or mass obtained by a reacting mass calculation
Atom Economy
shows how many of the atoms used in the reaction become the desired product. Rest is wasted
- In addition reactions, the atom economy will always be 100%, because all of the atoms are used to make the desired product
- Whenever there is only one product, the atom economy will always be 100%
Atom Economy formula
Molar Mass of desired product / Sum of all molecular masses of all reactants * 100
Environmental Considerations of atom economy
Efficient processes have high atom economies and are important to sustainable development
- They use fewer resources
- Create less waste
