Flashcards in Topic 9 - Seperate Chemistry Deck (36):
What colour flame would Li+ ions give off of present in the flame test for metal ions ?
What colour flame would be given off when Na+ ions are present in sample?
What colour would K+ give off in the flame test for metal ions?
What colour flame would Ca2+ give off in the flame test?
What colour flame would be given off by Cu2+ in the flame test for metal ions ?
Describe the method for the flame test - for metal ions...
Firstly dip the wire loop into hydrochloride acid to remove impurities.Place loop in sample and that into outer blue flame of Bunsen burner
2 methods to test for metal ions ?
Flame test and Cation test
What colour is the precipitate formed from Al3+?
White, however it redissolves with excess NaOH to become colourless.
What colour is the precipitate of Ca2+ with NaOH?
What colour is the precipitate of Cu2+?
What colour is the precipitate of Fe2+?
What colour is the precipitate formed from Fe3+ ?
Red or brown
Method to form a coloured precipitate ?
Take a small sample of solution and test it drop wise with sodium hydroxide(NaOH)
What do you add to form a coloured precipitate ?
Sodium Hydroxide (NaOH)
Test for Ammonium Ions ?
Add sodium hydroxide solution, then heat and test if the gas given off is the ammonia gas. We can heck that by placing a red damp Lito is paper over the gas and if it turns blue then it contains ammonium ions..
What are the anion tests ?
Tests for halide, carbonates
and sulfate ions.
What are the halide ions?
Bromide, iodide and chloride
What is the method for the halide test?
1. To solution add nitric acid
2. Add silver nitrate
3. Watch the colour change of the precipitate
What colour is the chloride precipitate?
What is the chemical formula when chloride undergoes a halide year?
Ag+ + Cl- = AgBr
What colour is the precipitate of bromide after a halide test?
What is the formula of bromide precipitate after it undergoes a halide test?
Br- + Ag+ = AgBr
What is the formula of iodide after a halide test?
Ag+ + I- = AgI
What colour is the precipitate of iodide after it undergoes the halide test?
What is the method for the Carbonate test?
1. Add a dilute acid
2. If carbonates are present solution will fizz or bubble
What is the formula after a test for carbonates ?
Co2- + 2H+ = Co2 + H2O
How else can we check if carbon dioxide is given off in the carbonate test?
Use limewater , when CO2 present it will become milky
What is the method for the sulfates test?
1. Add hydrochloric acid
2. Add barium chloride.
3. Check if the solution turns white, this means sulfates are present
Formula after the test for sulfates ?
Ba2+ + SO(4)2- = BaSo4
What is the general formula for alcohols ?
Cn + H2n+1 OH
What happens to alcohols when they’re oxidised?
They become carboxylic acids
Example of an alcohol?
What functional group are alcohols a part of ?
What is the general formula for carboxylic acids ?
Cn-1 + H2n-1 COOH
What are alkenes?
A homologous series of unsaturated hydrocarbons with a C=C functional group