Criado por jadah Jacobs
aproximadamente 7 anos atrás
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Questão | Responda |
Are bases corrosive? | Yes |
Are acids corrosive? | Yes |
What does a litmus test tell us? | If the substance is acidic or basic (be careful it doesn't tell you how acidic it is - the ph level.) |
What is a precipitation reaction? | The formation of a solid from mixing two soluble solutions |
What does it mean if a substance is soluble? | Substance that can dissolve in water |
True or False: Most hydroxides are insoluble. | True - but the exception is group 1 metals |
Define Hydrocarbon | A compound that contains hydrogen and carbon atoms only |
Give the cation and flame colour of - Lithium | Li+ & red |
Give the cation and the flame colour of - Sodium | Na+ & orange |
Give the cation and the flame colour of - Potassium | k+ & lilac |
Give the cation and the flame colour of - Calcium | Ca2+ & yellow-red |
Give the cation and the flame colour of - Copper | Cu2+ & green-blue |
List the steps of testing for positive ions | 1. Clean the loop with HCL 2. dip it in the metal 3. Put it over the flame and identify what ion it is 4. Clean the loop with HCL 5. Repeat steps 1-5 |
State why flame photometry works better | 1. It can detect smaller amounts (sensitivity) 2. Accuracy 3. Its faster 4. Can separate mixtures of colours into an emission spectre. |
Which ion is this - Fe2+ | Iron (II) |
Which metal ion give out a precipitate color of brown/red | Iron (III) |
What do you have to do if you have two white precipitates formed? | You add excess sodium hydroxide to see if it is aluminium or calcium |
How do you know if the metal ion is Aluminium or Calcium? | Add excess sodium hyroxide if it turns back to a colourless solution then it is aluminium, if it stays white it is calcium |
State the chemical equation for copper nitrate mixed with sodium hydroxide | copper nitrate + sodium hydroxide --> copper hydroxide + sodium nitrate Cu (NO3)2 (aq) + NaOH (aq) --> Cu (OH)2 (s) + NaNO3 (aq) |
what is the net ionic equation for Cu (NO3)2 (aq) + NaOH (aq) --> Cu (OH)2 (s) + NaNO3 (aq) | Cu2+ (aq) + 2OH- ---> Cu(OH)2 |
How do you find a net ionic equation? | Simplify the equation then cross out all the things that are the same apart from the solid compound and the things that make up the solid compound |
Explain how you test for carbonates | 1. add a dilute acid 2. if it FIZZESthe test is positive for carbonate Metal carbonate + acid --> salt + carbon dioxide + water |
Explain how you test for sulphates | 1. add dilute hydrochloric acid 2. add borium chloide 3. If white precipitate is formed, the test is positive for sulphates Ba2+ (aq) + SO4 2- (aq) --> BaSO4 (s) |
Explain how you test for halides | 1. add dilute nitric acid (this acidifies the solution and removes any carbonate ions that might give a precipitate) 2. add silver nitrate 3. if precipitate is formed then the test is positive for halides |
What are halogens? | Group 7 non-metals |
Describe the hydroxide precipitate test for metal cations | 1. dissolve a little solid salt in a test tube using distilled water 2. Add a few drops of dilute sodium hydroxide 3. record the colour of the precipitate formed (if white add excess solution to see if it will disappear and leave a clear solution) |
state some properties of clay ceramics | Chemically unreactive, hard, stiff but brittle, poor eletrical and themal conductors, have high melting points and consist of giant structures with many strong bonds (covalent or ionic) |
define polymer | substances with high average relative formula masses |
define monomer | smaller molecules that join together to form repeating unit |
State some properties of polymers | strong, chemically unreactive, poo electrical and chemical conductors |
State some properties of some metals | hard, shiny solids, high melting points, good electrical and thermal comductors, malleable (pressed into shapes without breaking) |
what is 'a mixture of two or more mateials that have opposite properties (to hide weakness)' | A composite material |
Define tensile strength | lower tensile strength - more bendable higher tensile strength - not so bendable |
Define compressive strength | How well a material resists being squashed |
Define nanoparticle | a piece of material that consists of a few hundred atoms, usually 1nm - 100nm |
cube-shaped nanoparticle has sides of 20nm. calculate its total surface area, its volume, and surface area to volume ratio | total surface area = 6 x 20 x 20 volume = 20 x 20 x 20 suraface area to volume ratio = (6x20x20) / (20x20x20) |
If the total surafce area to volume ratio is higher what does that mean? | That there is more... |
What are the uses of nanoparticles dependent on? | - very small size - the total surface area to volume ratio |
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