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Natural sciences

Reactions that occur between different kinds of matter: acids and bases

Educator section

Memorandum

It is very important that you ensure beforehand that the substances collected by the groups are safe for tasting.

Black tea as indicator.

ACIDS NEUTRAL ALKALIS
Salt and vinegar Vanilla essence (sweet) Cocoa powder
Spices Instant soup (salty) Green pepper
Turmeric Apple vinegar Bicarbonate of soda
Lemon juice Chocolate

Leaner section

Content

Warning

  • All people have senses that enable them to observe different aspects of the environment. The tongue is the sense organ that makes it possible to observe the taste of substances. Never taste any substance if you are not altogether sure that it is harmless! People often store substances in containers that do not have the necessary labels. We quite frequently have dangerous substances in our homes, e.g. battery acid, ammonia and pool acid. Remember that it is unwise to taste anything that cannot be identified as harmless.

Activity: to identify acids and bases in and around the home [lo 1.2, lo 2.2]

Most acids have a sour taste, while most bases are bitter. The rear area of the tongue identifies these tastes. The foremost part of the tongue records the taste of substances that are sweet or salty. Substances such as these are neither acids nor bases, but are neutral.

Check through your mother's kitchen cupboards and bring some of the following to school with you:

Toothpaste

  • Ask your mother to help you ensure that you do not bring dangerous substances like ammonia or bleaching agents to school with you.
  • Form groups and draw up lists of the substances that you have in your group.
  • Get your educator's help in ensuring that all the substances are safe to taste.

Complete the following table by tasting all the substances and recording your observations.

ACIDSThese substances have a sour taste NEUTRALThese substances taste neither sour nor bitter BASESThese substances have a bitter taste
______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________
______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________
______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________
______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________
______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________

(15)

Compare your personal experience with the experiences of the other members of the group. Classify the substances in your group according to their taste. Compare your notes with those of the other groups.

  • Did everyone agree about the tastes of all the substances? __________________
  • If everyone did not agree, indicate where the differences occurred?

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

_____________________________________________________________________

Assessment

Learning Outcome 1: The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

Assessment Standard 1.2: We know this when the learner conducts investigations and collects data: organises and uses apparatus/equipment or sources to gain and record information.

Learning Outcome 2: The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

Assessment Standard 2.2: We know this when the learner categorises information.

Questions & Answers

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SUYASH Reply
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SUYASH
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s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
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Cied
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Porter
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Porter
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Uday
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AMJAD
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Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
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AMJAD
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AMJAD
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Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
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Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
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Prasenjit
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Damian
silver nanoparticles could handle the job?
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Azam
Hello
Uday
I'm interested in Nanotube
Uday
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Prasenjit
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Prasenjit Reply
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the Beer law works very well for dilute solutions but fails for very high concentrations. why?
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Source:  OpenStax, Natural sciences grade 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11077/1.1
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