Weaknesses Flashcards
(53 cards)
Describe the stages of Paper Chromatography
1) draw a line in pencil near the bottom on the filter paper
2) add a spot of the ink being investigated on the line and place the sheet in a solvent, make sure the solvent isn’t touching the ink
3) place the lid on the container to stop the solvent evaporating
4) each dye with move up the paper at different rates so they will form different spots
What does filtration separate?
Insoluble solids from liquids
What does evaporation separate and how is it completed?
Soluble solids from solutions:
1) pour the solution into an evaporating dish
2) slowly heat the solution until the solvent has evaporated leaving dry crystals
What does crystallisation separate and how is it completed?
Soluble solids from solutions:
1) pour the solution into an evaporating dish
2) once some crystals form, remove the dish
3) the salt should form crystals as it becomes insoluble
4) filter out the crystals and leave them in a warm place to dry
What are the products of an alkali metal and water?
metal hydroxide and hydrogen
What is the product of an alkali metal and chlorine?
Metal chloride slats
What is the product of an alkali metal and oxygen?
Metal oxides
What are the coloured vapours of: Flourine Chlorine Bromine Iodine
yellow
green
red-brown
purple
What are the structure and properties of ionic compounds?
A giant ionic lattice which has high melting and boiling points. Carry an electronic charge when molten or when dissolved in water.
What two types of element bond ionically?
A metal and a non-metal
What two types of element bond covalently?
Two non-metals
What are the properties of giant covalent structures?
Very high melting and boiling points. Don’t conduct electricity, even when molten, apart from exceptions like graphite.
What are the potential uses of fullerenes?
Could be used to deliver drugs in body. Huge surface area could make them good catalysts and they’re good lubricants.
What is the name of the force between the metal ions and the delocalised electrons in metallic bonding
Electrostatic
What are the properties of metals?
Solid at room temp because of strong forces between electrons and ions, good conductors of heat and electricity, maleable.
What is the typical diameter of a nanoparticle?
1-100nm
What is the formula for number of moles?
mass ÷ Mr
What is the formula for the volume of a know mass of any gas at r.t.p?
(mass + Mr) x 24
What is the formula for concentration?
no. of moles ÷ volume
What is the equation for atom economy and what does it tell us?
(relative formula mass of desired product ÷ relative formula mass of all reactants) x 100
It tells us what percentage of the reactants will be made into useful products
What is the equation for percentage yield and what does it tell us?
(mass of product made ÷ maximum theoretical mass) x 100
It compares what we actually have to what the maximum amount we could have is
What does an acid + a base give?
A salt and water
How do you complete a titration?
If you wanted to find the concentration of an alkali:
1) using a pipette, add a set volume (25cm3) of an akali to a conical flask add 2 - 3 drops of phenolphthalein
2) fill a burette with acid of known concentration and record the initial volume
3) add the acid to the alkali slowly.
4) the indicator changes colour (pink to clear) when all the alkali has been neutralised
5) record the final volume of the acid to work out the volume of the acid required to neutralise the alkali
6) use concentration calculations to work out the concentration of the alkali
What happens to strong acids in water?
All acid particles dissociate to release H+ ions
