Paper 2018 1C 2018 Flashcards
What piece of apparatus can has a tap and can be used to dispense HCL?
Tap funnel
Give a reason why carbon dioxide can be collected by downward delivery in air?
It is more dense than air
Give another method of collecting carbon dioxide
(gas) syringe / over water
State the change in colour of the solid when copper(II) carbonate decomposes.
From Green the Black
Suggest properties of carbon dioxide that make it suitable for use in fire extinguishers?
- Does not support combustion
- more dense than air
- can be compressed (into a
fire extinguisher cylinder) - does not conduct electricity
A teacher investigates the reaction between sodium and water.
State observations that are made during the reaction.
- Bubbles of effervescence
- sodium gets smaller /disappears
- sodium moves/darts around
- white trail
- melts/forms a ball
- litmus/solution/liquid turns blue
A student tries to make a pure, dry sample of hydrated cobalt(II) chloride crystals.
He uses dilute hydrochloric acid and solid cobalt(II) oxide.
Step 1 pour about 50 cm3
of dilute hydrochloric acid into a beaker
Step 2 warm the acid using a Bunsen burner
Step 3 add a small amount of cobalt(II) oxide and stir the mixture with a glass rod
Step 4 add further small amounts of cobalt(II) oxide until it stops reacting
Step 5 filter the final mixture and collect the filtrate in an evaporating basin
Step 6 leave the filtrate until all of the water has evaporated
State why it is not necessary to have a precise measurement of the volume of
hydrochloric acid in step 1.
(because) all of the acid/HCl
is reacted/used up
Describe how you can produce a pure, dry sample of crystals from a filtrate?
A student tries to make a pure, dry sample of hydrated cobalt(II) chloride crystals.
He uses dilute hydrochloric acid and solid cobalt(II) oxide.
Step 1 pour about 50 cm3
of dilute hydrochloric acid into a beaker
Step 2 warm the acid using a Bunsen burner
Step 3 add a small amount of cobalt(II) oxide and stir the mixture with a glass rod
Step 4 add further small amounts of cobalt(II) oxide until it stops reacting
Step 5 filter the final mixture and collect the filtrate in an evaporating basin
Step 6 leave the filtrate until all of the water has evaporated
1) Heat or boil the filtrate in an evaporating basin
2) Until it has reached its crystallisation point or until the solution is concentrated.
3) Leave the solution and filter to remove crystals
4) Wash the crystals with a small amount of deionised water
5) Dry the crystals on filter paper or a tissue.
Chemical equation for changes from the purple CoCl2.2H20 to CoCl2.6H2O?
CoCl2.2H2O + 4 H2O –>
CoCl2.6H2O
Which of these words describes the change taking place when the pink solid
is heated to form the blue solid?
CoCl2.6H20 to CoCl2
The only correct answer is B because when the pink
solid CoCl2.6H2O is heated to from the blue solid CoCl2 it
is losing water which is dehydration
What is the test for ammonium ions?
Add dilute sodium hydroxide and warm.
Gas given off, gas turns damp litmus paper from red to blue.
Lilac coloured flame test?
Potassium
Test for carbonates?
Add dilute hydrochloric acid - reaction. Reaction with effervescence.
Test for halides?
Add dilute nitric acid and a few drops of silver nitrate solution.
Chloride - White
Bromide - Cream
Iodide - Yellow
Test for sulphates?
Add dilute hydrochloric acid
Drops of Barium Chloride
