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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

explain and give four Example hyperbolic function
Lukman Reply
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
SABAL Reply
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
Pawel
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Ifeanyi
on number 2 question How did you got 2x +2
Ifeanyi
combine like terms. x + x + 2 is same as 2x + 2
Pawel
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
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how do I set up the problem?
Harshika Reply
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I need quadratic equation link to Alpa Beta
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find the value of 2x=32
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divide by 2 on each side of the equal sign to solve for x
corri
X=16
Michael
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
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yes i wantt to review
Mark
use the y -intercept and slope to sketch the graph of the equation y=6x
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hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
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4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
can you teacch how to solve that🙏
Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
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x+2y-z=7
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what is the coefficient of -4×
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-1
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the operation * is x * y =x + y/ 1+(x × y) show if the operation is commutative if x × y is not equal to -1
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How do i figure this problem out.
how do you translate this in Algebraic Expressions
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why surface tension is zero at critical temperature
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I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
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Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
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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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