Testing for Elements

Question	Answer
Test for H- lighted splint goes out with a squeaky pop Test for O- glowing splint lights Test for CO2- limewater goes cloudy Test for Cl- bleaches damp red and blue litmus paper	Test for H2O purity - pure water boils at 100C -If water is impure than it boils higher than 100C -NB if water is impure it freezes below 0C hence salt on road in winter
Test for NH3 -Smells of stale urine -Made by heating an Ammonium coumpound with Sodium Hydroxide -The only alkali gas -IT TURNS RED LITMUS PAPER BLUE	Testing for Cations Some give a characteristic colour in a flame Li- deep red (crimson) Na- Orange K-Lilac Ca-Brick Red
Not many Cations give colours in a flame therefore we have to use a different test Adding Sodium Hydroxide solution we can identify 4 with this test	We add 2cm3 of each substance to a test tube We add NaOH drop by drop using a teat pipette
Iron(II) Sulphate-Dark Green Participate Iron(III) Sulphate-Orange Participate Copper Sulphate-Blue Particpate	The 4th Cation is Ammonium however it doesnt form a participate, but on gentle heating Ammonia gas is given off Smell of stale urine and red litmus turns blue
Testing for Anions Add dilute Nitric acid, followed by Silver Nitrate solution Chloride Compound-White Percipitate Bromide Compound-Cream Percipitate Iodide Compound- Yellow Prcipitate	Test for SO4- add dilute HCl followed by BaCl2, which should form a white percipitate BaSO4 Test for CO3- add acid, Carbon Dioxide will be given off which turns lime water cloudy

Resource summary

	Created by Konrad O'Neill over 11 years ago