Transcript Smart materials & nanoscience - science

OCR SCIENCE – UNIT 1 BEST PRACTICE
Chemical testing
for Ions
Prior learning
Chemicals can react together and change colour
Key words
React, precipitate, colour change, identify, Cations,
Anions
OCR SCIENCE – UNIT 1 BEST PRACTICE
I am learning to: identify cations and anions in different solutions by their
colour change
I will be successful if I can:
• Describe the term cation and anion and explain the test to be carried out
• Carry out a practical activity safely (having completed a risk assessment) to
confirm the presence of different cations an anions
• Complete a table to show results of practical tests
• Conclude, Evaluate and comment on reliability of the test
Outcome: I can identify unknown ions in a given solution.
TO ACHIEVE A MERIT:
1. Add DETAIL to your report by explaining what is happening in each step
using the guidance sheets.
2. Relate the results of the test back to the scenario of students becoming ill
having played on the playing fields.
3. Complete an aim, prediction and method in handwritten form to add to your
testing notes.
Any of these can be completed at home or with Ms C’s help at break, lunch or
after school.
I am learning to:identify cations and anions in different
solutions by their colour change
Introduction: what are ions?
• Ions are charged particles.
• Positively charged particles
are called CATIONS
(because they are attracted
to the negative electrode
called the cathode which are
usually metals)
• Negative Ions are called
ANIONS because they are
attracted to the anode
these are usually non-metals
I am learning to:identify cations and anions in different
solutions by their colour change
Reference
Ion
Test
Result
Chloride
Add Silver nitrate Solution
White precipitate
Sulphate
Add acidified Barium chloride
solution
White precipitate
Carbonate
Add dilute acid and test gas with
limewater
Milky white precipitate
Copper (Cu++)
Add Sodium hydroxide solution
Blue precipitate
Iron
Add Sodium hydroxide solution
Brown precipitate
I am learning to:identify cations and anions in different
solutions by their colour change
Reference
Copper
Cations
Sodium hydroxide
Iron
Cations
I am learning to:identify cations and anions in different
solutions by their colour change
Reference
Acid
Carbonate
Anions
Chloride
Anions
Silver Nitrate
I am learning to:identify cations and anions in different
solutions by their colour change
Reference
Sulphate
Anions
Barium
Chloride
I am learning to:identify cations and anions in different
solutions by their colour change
Risk Assessment
Department:
Science
Brief summary of activity: Chemical
Room Number:
R4
tests for chlorides, sulphates and carbonates
List hazardous procedures and the
hazards) relating to them
Procedure
Hazard
Using squirt bottles & glass
Chemical in eye, broken glass cuts
List the substances hazardous to
health and the hazards) relating to them
Substance
Hazard
chemicals
Irritant, harmful and corrosive
Risk and Safety phrases
Wear goggles
List who might be exposed to the
hazard substance(s).
(e.g. staff, students, visitors, cleaners)
Assessing the level of risk
How severe is any injury or health effect likely to be? Medium
Staff & pupils
How likely is exposure to the hazard? Medium
What is the overall level of risk? (Tick appropriate box – if risk is high further steps must be taken to
minimum the risk of the procedure)
High
Emergency Procedures
(first aid actions, fire actions, spill action)
Wash hands under cold water
Wipe up any spills
Brush up broken glass and put in glass bin
Disposal requirements
Date:
Technician to dispose of waste in prep room
Name:
Signature:
x
Medium
Low
I am learning to:identify cations and anions in different
solutions by their colour change
Results
Test
A
Add Silver nitrate solution
Add acidified Barium chloride
solution
Add dilute acid and bubble gas
through limewater
Add Sodium hydroxide
Sample ion
B
C
Samples
Soil Water
I am learning to:identify cations and anions in different
solutions by their colour change
Results
Test
Samples
1
2
3
water
soil
yes
X
X
Yes
X
Add acidified Barium chloride
solution
X
Yes
X
X
X
Add dilute acid and bubble gas
through limewater
X
X
X
X
X
X
yes
X
yes
sulphate
copper
chloride
Iron
Add Silver nitrate solution
Add Sodium hydroxide
x
Sample ion
chloride
I am learning to:identify cations and anions in different
solutions by their colour change
Conclusion of findings
•
Conclusion of findings:
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
_______________________________________________________________
I am learning to:identify cations and anions in different
solutions by their colour change
Reliability
1.
Do qualitative tests tell you how much of a substance is
present?
No, just if the substance is present
2. If the test substance is a mixture will one get clear results?
No more than one result may show
3. Will the tests work if the substance is insoluble?
no
4. Is there an amount of substance needed to get a positive test?
Small amounts of each substance should work
5. Can your test substances be contaminated?
Yes if clean pipettes are not used
I am learning to: view samples using a microscope and test samples for metals using
flame tests
HOMEWORK
Complete the associated worksheet on
Chemical tests
Approx. 10mins
OCR SCIENCE – UNIT 1 BEST PRACTICE
I am learning to: identify cations and anions in
different solutions by their colour change
I will be successful if I can:
• Describe the term cation and anion
• Carry out a practical activity safely to confirm the
presence of different cations an anions
• Complete a table to show results of practical tests
Outcome: I can identify unknown ions in a given
solution.
I am learning to:identify cations and anions in different
solutions by their colour change
Summary – draw the colour changes of each
test on plain paper
Copper
Cations
Sodium hydroxide
Iron
Cations