Mixtures Flashcards
What is the state symbol for a solid?
(s)
What is the state symbol for a gas?
(g)
What is the state symbol for a liquid?
(l)
What is the state symbol for an soluble substance in water or aqueous?
(aq)
When is a substance aqueous?
When the substance is soluble in water and water is present in the reaction
Give the types of salt which are always soluble
All nitrate salts are soluble
All sodium, potassium (group 1) or ammonium salts are soluble
State the solubility rule for halides
All Halides are soluble except for lead and silver
State the solubility rule for sulfates
All sulfates are soluble except for lead and barium
Which of the following salts are soluble?
Na2CO3 BaSO4 Mg(NO3)2 PbCl2
Na2CO3 Mg(NO3)2 are soluble
BaSO4PbCl2 are insoluble
All sodium salts are soluble
All nitrate salts are soluble
All sulfate salts are soluble except for Barium
All halide salts are soluble except for lead
State the solubility rules for oxides, hydroxides and carbonates
All oxide, hydroxides and carbonates are insoluble except for sodium, potassium or ammonium
Outline the method for chromatography
- draw a pencil line at the bottom of the paper using a ruler
- create dots of ink along the pencil line
- curl the paper into a cylinder (with the pencil line at the bottom) and fasten with a paper clip at the top
- add a small amount of water to a beaker
- stand the cylinder with the pencil line at the bottom in the baker making sure the water level is below the pencil line
- leave until the solvent front approaches the top of the paper- remove the chromatogram
- mark the solvent front and leave to dry
What is the pencil line called on a chromatogram?
The base line
When carrying out chromatography, why must the water level be below the pencil line (base line)?
Otherwise the ink samples would dissolve into the water and would not travel up the paper. You want the water to move up the paper- taking the ink with it.
What is the formula for finding the Rf value of an pigment in chromatography?
Rf= distance pigment moved from base line / distance solvent moved from base line
Remember your Rf values will always be less than 1.
You are using a ruler so you must measure to a mm. It is best to record the distance in mm to avoid any mistakes.
When carrying out chromatography on a sample of inks, what does it mean if the ink does not move from the base line?
That particular ink is insoluble in that solvent
When Alex carried out chromatography, none of his ink samples moved from the base line. What could Alex do to get the ink to move from the base line so that he can compare the ink samples?
The ink samples are not soluble in that solvent. Alex should change the solvent.
Amelie noticed that one sample of ink did not separate into different spots as it travelled up the chromatography paper, but it stayed as one spot. What can Amelie conclude about that sample of ink?
That sample of ink is soluble in water but is a pure sample with only one pigment. It is not a mixture of two pigments.
Amelia noticed that one sample of ink separated into two different spots as it travelled up the chromatography paper, with one dot travelling further than the other. What can Amelia conclude about that sample of ink?
That sample of ink is soluble in water but is a mixture of two pigments. It is not pure, not one pigment.
Note: One pigment is more soluble than the other and travels further up the paper.
In chromatography, what is the relationship between solubility of a pigment and its Rf value?
The more soluble a pigment is the further it travels up the paper, the larger the Rf value.
note: an Rf value can never be larger than 1
What doe the symbol Rf stand for?
Retardation factor
In filtration, what is the name of the substance which is trapped in the filter paper?
The residue
In fitration, what is the name of the substance which passes through the filter paper.
The filtrate
Which method below would separate water from salt?
filtration
chromatography
simple distllation
fractional distillation
evaporation
simple distillation
The water would evaporate and then condense in the Leibig condenser, dripping out the end as the distillate
Which method below would separate salt from seawater?
filtration
chromatography
simple distllation
fractional distillation
evaporation
evaporation
when heated, the water evaporates leaving the salt crystal behind.
Which method below would separate alcohol from water?
filtration
chromatography
simple distllation
fractional distillation
evaporation
Fractional distillation
The fractionating column contains glass beads which gives the inside of the column a very large surface area. If the temperature near the condenser is kept at 78 degrees (the boiling point of alcohol) alcohol and some water will evaporate from the solution and travel up the column. The large surface area allows the water to condense on the glass beads and drips back into the flask. Only the alcohol enters the condenser and dripps out the end as a pure alcohol distillate
Which method below would separate an insoluble salt from water?
filtration
chromatography
simple distllation
fractional distillation
evaporation
filtration
The insoluble salt is solid and is caught in the filter paper as the residue.
Note: it is best to wash the insoluble salt with distilled water to make a pure sample
Which method below would separate an insoluble salt from water?
filtration
chromatography
simple distllation
fractional distillation
evaporation
filtration
The insoluble salt is solid and is caught in the filter paper as the residue.
Note: it is best to wash the insoluble salt with distilled water to make a pure sample
Which method below would separate an ink sample?
filtration
chromatography
simple distllation
fractional distillation
evaporation
Chromatography
The most soluble pigment will travel the furthest up the chromatography paper.
Which method below would separate soluble salt from water?
filtration
chromatography
simple distllation
fractional distillation
evaporation
Evaporation
The salt is soluble, so filtration will not work. You must heat the solution and evaporate the water, leaving the salt behind
Which piece of equipment is used to separate two immiscible liquids?
Separating funnel
The less dense liquid will sit on top of the more dense liquid. When the layers have time to fully separate, the tap is open at the bottom of the funnel and the more dense liquid pours out.
Define a solvent
A liquid which dissolves a solute
Define a solute
A solid which dissolves in a solvent
Define a solution
A solution is formed when a solute dissolves in a solvent
What equipment would you need to carry out evaporation of a salt solution?
evaporating basin
Bunsen burner
heat proof mat
gauze
What equipment would you need to filter sand from water?
filter funnel
filter paper
beaker
How would you obtain pure salt from rock salt?
- grind rock salt in a pestle and mortar
- add water and stir to dissolve salt
- fold filter paper and place in filter funnel
- place filter funnel in beaker
- pour solution into filter paper in parts- make sure to keep level of solution below edge of filter paper.
- collect filtrate in beaker
- Set-up evaporating basin over Bunsen burner using a tripod and gauze.
- Pour filtrate in evaporating basin
- Heat solution on medium flame until half volume
- Leave solution to crystallise
- Filter out crystals
- Leave crystals to dry in warm place
How is mass of solute which dissolves related to the volume of solvent?
As the volume of solvent doubles, the mass of solute which dissolves doubles. They are proportional?
In chromatography, if a pigment or ink is not soluble in a solvent what would you observe?
The pigment would not move from the base line. Rf value would be zero.
What is the valency of a lead ion?
Pb 2+
What are the two possible valencies of copper ions?
Cu 1+ and Cu 2+
What are the two possible valencies of iron ions?
Fe 2+ and Fe 3+
What is the valency of a silver ion?
Ag 1+
What is the valency of a zinc ion?
Zn 2+
What is the valency of a hydrogen ion?
H +
What is the valency of a hydroxide ion?
OH 1-
What is the valency of a carbonate ion?
CO3 2-
What is the valency of a nitrate ion?
NO3 -1
What is the valency of a sulfate ion?
SO4 2-
What is the valency of an ammonium ion?
NH4 +
I am a type of salt which is insoluble if I am bonded with a lead or barium metal? What type of salt am I?
sulfate salt
I am a type of salt which is insoluble if I am bonded with a lead or silver metal? What type of salt am I?
halide salt
I am measured in g per 100 cm3
What am I?
solubility