Testing for Ions Flashcards
what are the precautions to be taken when working with a toxic substance
use a fume cupboard
wear protective gloves
what are the precautions to be taken when working with a corrosive substance
wear safety goggles
wear protective gloves
what are the precautions to be taken when working with an irritant
wear safety glasses
wear protective gloves
use a dust mask
what is the test for chlorine
test the gas with damp blue litmus paper, it first turns red and then bleaches
what is the test for ammonia
test the gas with damp red litmus paper, it turns blue
what are the different ways of collecting gases
collected over water (if the gas is insoluble)
collected by upward delivery (if the gas soluble in water and less dense than air)
collected by downward delivery (if the gas is soluble in water and denser than air0
how do you measure the volume of a gas
using a gas syringe
how do you carry out a flame test
clean a platinum wire loop using HCL.
Pick up a small amount of the solid using the wire loop
Heat the solid in the edge of a blue bunsen flame/roaring flame
observe and the record the colour of the flame
what are the different colours of positive ions in a flame test
lithium
sodium
potassium
calcium
copper
lithium - red
sodium - yellow
potassium - lilac
calcium - orange red
copper - blue green
why is it difficult to identify 2 different ions in a compound using a flame test
the two colours would mix together
what are the advantages of instrumental methods of analysis over flame tests
more sensitive
more accurate
more rapid
what can a flame photometer do
identify the metal ions in a substance and measure the concentrations of metal ions
how is a metal ion in an unknown solution identified
matching its spectrum to the spectrum from a known metal ion
why is distilled water used to make the standard solutions rather than tap water
tap water contains dissolved metal ions which may interfere with the results
distilled water does not contain metal ions
how is a calibration curve for the concentration of K+ ions produced
using standard solutions of K+ ions and a flame photometer