CKS3: Yr7 Chemistry Unit 1

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CKS3 Yr7 Chemistry Unit 1 Me the the
Scientist!Lesson number 4. Lesson Title Acids
and Alkalis
Learning Outcomes How I did Targets
Learning Outcome 1 Use the pH scale to identify the pH of different acids and alkalis Level 5
Learning Outcome 2 Link pH of an acid or alkali to how hazardous or corrosive it is. Level 6
Learning Outcome 3 Link strength of an acid to how corrosive it is. Level 7 .

• Connector
• List 3 common acids and 3 common alkalis and how
  they are used at home.

Cro2011
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New Information for Task 1

• Acids and alkalis are groups of chemicals.

ALKALI
ALKALI
ACID
ACID
ALKALI
NEUTRAL
ACID
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Acids and alkalis
When a substance dissolves in water it makes a
solution.

• Solutions can be sorted by whether they are
  acid, alkali or neutral.

http//www.bbc.co.uk/learningzone/clips/universal-
indicator-acid-alkali-or-neutral/121.html
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Some facts about acids and alkalis
New Information for Task 1
ACIDS ALKALIS
Sharp, sour taste Soapy feel
Strong acids can corrode (eat away) metals, e.g. hydrochloric acid Strong alkalis can corrode metals, e.g. sodium hydroxide
Some can burn living tissue, e.g. battery acid, other kinds wont, e.g. lemon juice Can be caustic (burn living tissue), e.g. caustic soda for oven cleaning
Some are hazardous, e.g. sulphuric acid, some are harmless, e.g. vinegar Some are hazardous, e.g. sodium hydroxide, some are harmless, e.g. sodium bicarbonate (baking powder)
Neutralise (cancel out) alkalis Neutralise (cancel out) acids
Turn litmus indicator RED Turn litmus indicator BLUE
Have a pH of 1-6 Have a pH of 8-14
Examples hydrochloric acid sulphuric acid nitric acid citric acid (lemons, oranges etc) vinegar soap (Johnsons pH 5.5) Examples Sodium hydroxide (caustic soda) ammonium hydroxide (ammonia) calcium hydroxide (limewater) Washing powder Oven cleaner soap
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BIG picture
Key Question How can you determine if a chemical
is an acid or an alkali?
How is this lesson relevant to every day life?
There are many acids and alkalis present in our
everyday lives.
What skills will you be developing this
lesson? HSW- by planning and carrying out an
investigation/ Interpreting data/ evaluating an
experiment ICT- through using laptops Numeracy-
by using formulae in calculations Literacy- by
writing explanations using correctly spelt
keywords and good grammar. Team work- during a
practical investigation Self management- by
completing an individual assignment by
.. Creative thinking- by designing a
. Independent enquiry- by researching the
internet Participation- during a practical
activity Reflection- through self and peer
assessment of each outcome
Quick Discussion What do you already know?
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Keywords
Create sentences using the keywords to show that
you know what they mean. Put your hand up if
there is any key word from the list that you
dont understand.

• Acid
• Alkali
• Solution
• pH
• Indicator
• Universal Indicator
• Sour taste
• Soapy feel
• Caustic

• Irritant
• Strong
• Weak
• Corrode
• hazardous

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New Information for Learning Outcome 1

• Visual Demonstration
• http//www.bbc.co.uk/learningzone/clips/universal-
  indicator-acid-alkali-or-neutral/121.html
• Audio Demonstration
• Kinaesthetic Class experiment

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What is the pH scale?
The strength of an acid or alkali is measured by
the pH scale.
Each universal indicator colour is given a number
called the pH value.
Universal indicator can tell you the pH of a
solution.
stronger alkali
stronger acid
1 2 3 4 5 6 7 8 9 10 11 12 13 14

weak alkali
strongacid
weakacid
strongalkali
neutral
What is the pH of a weak acid? What is the pH of
strong alkali?
Copy into books
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Task 1 (Level 5)

• Task 1
• Predict from the range of household substances
  which ones you think are acids and alkalis, write
  them down in predictions
• Task 1 Extension
• Group the substances into strong and weak acids
  and strong and weak alkalis

• Keywords for Task 1
• Acid
• Alkali
• Weak Acid
• Weak Alkali
• pH
• Universal indicator

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Copy and complete
Substance Prediction, acid or alkali? Colour and pH Acid or alkali?
Milk
Apple juice
Orange juice
Lemonade
Cola
Vinegar
Bleach
Water
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What type of substance?

• Are these substances acidic or alkaline?
• Are they weak or strong?

Substance pH Description of acid/alkali
soda water 6
car battery acid 1
soap 8
washing soda 10
stomach acid 2
oven cleaner 14
vinegar 4
very weak acid
very strong acid
very weak alkali
weak alkali
strong acid
very strong alkali
weak acid
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Demonstrate your Learning for Outcome 1
I am working at level .... because ...........
Apply (L5) Can you use a storey board to explain
how to identify if a household substance is an
acid, alkali or neutral

• Understand (L4)
• Did you
• Complete the experiment ?
• Can you classify different household substances
  into acid or alkali?

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Extended Learning

• Extended Learning task
• Make a poster display of all the different acids
  and alkalis in the home and their different uses.
• e.g. Vinegar is an acid and it can be used in
  homes to make pickles.
• Due date
• Criteria for Level 5
• Basic description, basic detail.
• Criteria for Level 6
• Description with explanation and good level of
  detail.
• Criteria for Level 7
• Detailed description and in depth detailed
  explanation using examples to highlight points
  made.

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Learning Outcome 1 Review
To carry out an experiment to identify and
classify household substances into acids and
alkalis
Go back to your Learning Outcome grid and fill
out the How I did and the Targets column.
Learning Outcome How I did Targets
Learning Outcome 1 Level 5 Met? Partly met? Not met? How can I improve on Learning Outcome 1?
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New Information for Learning Outcome 2
What are hazard symbols?
How can you tell which chemicals are safe and
which are dangerous? Special symbols are used on
bottles and vehicles that contain dangerous
chemicals.
corrosive
harmful
irritant
toxic
highly flammable
These hazard symbols show why the chemical is
dangerous. Why is it important that these
symbols can be recognised by
people from other countries?
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7E Acids and alkalis - Concentrated and dilute
Compare the particle model of a concentrated acid
with a weak acid.
Which sentence best describes which acid?
A. This acid has only a few acid particles
compared to water particles.
B. This acid has a lot of acid particles
compared to water particles.
Why is a dilute acid less hazardous than a
concentrated acid?
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Demonstrate your Learning for Outcome 2
I am working at level .... because ...........
To get to the next level I need to ...........

• Analyse (L6)
• Did you
• Draw a poster to identify hazard warning symbols
• Include pictures of the chemicals and information
  about how to use it safely in the lab?
• Explain why dilute acid is less hazardous

• Apply (L5)
• Did you
• Do a storey board to explain what happen when UI
  is added to a substance
• Identify the colour change with UI?

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Learning Outcome 2 Review
To carry out an experiment to investigate the
heating effect of different bunsen flames.
Go back to your Learning Outcome grid and fill
out the How I did and the Targets column.
Learning Outcome How I did Targets
Learning Outcome 2 Level 6 Met? Partly met? Not met? How can I improve on Learning Outcome 2?
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Learning Activities for Outcome 3
Extension Linking the strength of an acid to
how corrosive it is
Task 7 Draw a line, and add substances to it
to show how hazardous or corrosive you think the
household substances are Task 2 Extension Name
a very harmful acid and very harmful alkali
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Task 3 Answers
Not harmful Weak acids and alkali and neutral
Harmful and corrosive Strong acids and Alkalis
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Learning Outcome 3 Review
Go back to your Learning Outcome grid and fill
out the How I did and the Targets column.
Learning Outcomes How I did Targets
Learning Outcome 3 Level 7 Met? Partly met? Not met? How can I improve on Learning Outcome 3?
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Review for Remembering

• Stand up if you have met the lesson outcomes?
• If not what do you need to do next in order to
  meet the outcome? Record this in your diary as
  part of your homework.
• Is there any part of the lesson you think you
  need to go over again next lesson?
• Tell the person next to you three things you have
  learnt this lesson.
• How will you remember this for your exam?

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Technicians list Apparatus and chemicals Eye
protection Universal Indicator fizzy drinks
tap water de-ionised/distilled water
toothpaste shampoo soap vinegar lemon
juice Technical notes 1 Provide small amounts of
the samples on watch glasses. The watch glasses
can be placed on a white tile marked with the
name of the substance - use a waterproof marker.
2 The samples can be arranged around the room so
that the students visit each in turn. If any
solid sample is used, moisten it with a little
de-ionised water.