unit 10 unit 10 summary check-point unit 10 unit 10 summary check-point
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Unit Unit 1010
Summary Summary checkcheck--
pointpoint
Unit Unit 1010
Summary Summary checkcheck--
pointpoint
Acids & alkalis in daily lifeAcids & alkalis in daily life10.110.1 10.110.1 p.57p.57
1 1 Acids taste ______ Acids taste ______ (a)(a) but alkalis tast but alkalis tast
e ______ e ______ (b) (b) ..
soursour
bitterbitter
2 2 The colour of red cabbage extractThe colour of red cabbage extract
is ______is ______ (a) (a) in acids & ________ in acids & ________ (b) (b) in in
alkalis.alkalis.
redred green green
3 3 Some plant extracts contain pigmenSome plant extracts contain pigmen
ts that can change colour in acids & ts that can change colour in acids &
alkalis. They can be used as _____alkalis. They can be used as _____
_________________ _________________ (a)(a) . .natural indicatorsnatural indicators
4 4 The commonly used laboratory ____The commonly used laboratory ____
_____ _____ (a) (a) include hydrochloric acid, niinclude hydrochloric acid, ni
tric acid and sulphuric acid. The cotric acid and sulphuric acid. The co
mmonly used laboratory __________ mmonly used laboratory __________
(b) (b) include sodium hydroxide & amminclude sodium hydroxide & amm
onia solution. onia solution.
10.210.2 10.210.2 Laboratory acids & alkalisLaboratory acids & alkalis
alkalis alkalis
acids acids
5 5 We should take the necessaryWe should take the necessary
___________________ ___________________ (a)(a) when when
handling acids & alkalis. We handling acids & alkalis. We must use them carefullymust use them carefully. .
6 6 Common indicators used in the Common indicators used in the
laboratory arelaboratory are _________ _________ (a) (a) & ___& ___
_______________ _______________ (b)(b) . .
litmus litmus
universal indicator universal indicator
safety precautions safety precautions
p.58p.58
7 7 Blue litmus turnsBlue litmus turns ______ ______ (a)(a) in acids. Rin acids. R
ed litmus turnsed litmus turns ______ ______ (b)(b) in alkalis. in alkalis.
redred
blueblue
8 8 Universal indicator changes toUniversal indicator changes to
_____ _____ (a)(a) in acids &in acids & ______ ______ (b) (b) in alkalis in alkalis
with a series of colours with a series of colours
in betweenin between.. It is green in colour It is green in colour
in _________ in _________ (c)(c) substances. substances.
redred blueblue
neutralneutral
9 9 The _________ The _________ (a) (a) tells the degree of atells the degree of a
cidity & alkalinity of substances. Tcidity & alkalinity of substances. T
he pH value ranges from_____ he pH value ranges from_____ (b) (b) to _to _
___ ___ (c) (c) ..
>> The pH value of _________ The pH value of _________ (d) (d)
substances is below 7.substances is below 7.
>> The pH value of _________ The pH value of _________ (e) (e)
substances is 7.substances is 7.
>> The pH value of _________ The pH value of _________ (f) (f)
substances is above 7.substances is above 7.
pH scalepH scale
acidicacidic
neutralneutral
alkalinealkaline
141400
10 10 It is important for the different parts of It is important for the different parts of our body to maintain their ________ our body to maintain their ________ (a) (a)
pH levels so that our body can functiopH levels so that our body can function properly. For plants, the availability n properly. For plants, the availability of nutrients depend on the acidity or aof nutrients depend on the acidity or alkalinity of the ______ lkalinity of the ______ (b) (b) ..
10.310.3 10.310.3
Importance of keeping the Importance of keeping the right pHright pH
properproper
soilsoil
11 11 Many daily used products like Many daily used products like cosmetics & personal care products scosmetics & personal care products s
how their ___________ how their ___________ (a) (a) on their pacon their pac
ks.ks.
pH valuespH values
12 12 We can test for We can test for ________________ ____________ (a)(a)
by placing a burning splint at the by placing a burning splint at the
mouth of the test-tube full of the gmouth of the test-tube full of the g
as. It gives out a ‘pop’ sound.as. It gives out a ‘pop’ sound.
10.410.4 10.410.4 The corrosive effect of acids The corrosive effect of acids
hydrogen gashydrogen gas
13 13 Dilute acids react with some metalsDilute acids react with some metals
to give _____________ to give _____________ (a) (a) . The acid. The acid
s are __________ s are __________ (b) (b) to these metals.to these metals.
hydrogen hydrogen
corrosivecorrosive
14 14 Dilute acids also react with building Dilute acids also react with building
materials made ofmaterials made of _______________ _______________
(a) (a) to giveto give _______________ _______________ (b) (b) . . ThatThat
is why acids corrode our buildings is why acids corrode our buildings & statues.& statues.
calcium carbonatecalcium carbonate
carbon dioxidecarbon dioxide
marblemarble
limestonelimestone
sandstonesandstone
15 15 The average pH value of rainwater iThe average pH value of rainwater i
s about s about ______ ______ (a) (a) becausebecause ________ ________
_______ _______ (b) (b) in thein the air can dissolve in air can dissolve in
it . The pH of acid rain is belowit . The pH of acid rain is below ___ ___
___ ___ (c) (c) 。 。
carbon dioxidecarbon dioxide
5.65.6
5.65.6
10.510.5 10.510.5 Acid rain Acid rain ———— the invisible threatthe invisible threat
1616 _________ _________ (a) (a) is formed whenis formed when acidic acidic
gases like _________________ gases like _________________ (b) (b) & &
_______________ _______________ (c) (c) dissolve in the dissolve in the
rainwater. The acidic gases are givrainwater. The acidic gases are giv
en off from factories, power stationen off from factories, power station
s & vehicles.s & vehicles.
sulphur dioxidesulphur dioxide
nitrogen oxidesnitrogen oxides
acid rainacid rain
17 17 The harmful effect of acid rain is The harmful effect of acid rain is
slow but destructive. Itslow but destructive. It _________ _________ (a) (a)
our buildings & statues. It can alsoour buildings & statues. It can also
___________ ___________ (b) (b) in our rivers, lakes in our rivers, lakes
& the sea. It can affect the& the sea. It can affect the _______ _______
__________ __________ (c) (c) by turning the soil by turning the soil
acidic & toxic.acidic & toxic.
corrodescorrodes
destroy lifedestroy life
18 18 We can help reduce air polluWe can help reduce air pollu
tion by using ________ tion by using ________ (a) (a) momo
re efficiently.re efficiently.
energyenergy
p.59p.59
growthgrowth
of plantsof plants
19 19 Acids can be used to Acids can be used to _________ _________ (a) (a)
food because it can stop the food because it can stop the growth of micro-organisms.growth of micro-organisms.
10.610.6 10.610.6 Everyday uses Everyday uses of acids & alkalis of acids & alkalis
preservepreserve
20 20 _________ _________ (a)(a) contains acetic acid acontains acetic acid a
nd is commonly used for food prend is commonly used for food pre
servation.servation.
VinegarVinegar
21 21 Fruits like apple, banana, pear and Fruits like apple, banana, pear and
peach turn brown when they are cupeach turn brown when they are cu
t and left in the air for a period of tit and left in the air for a period of ti
me. Acids can prevent fruits from me. Acids can prevent fruits from __
____________________ (a)(a) 。。browningbrowning
22 22 Acids & alkalis are commonly used Acids & alkalis are commonly used
as as ___________________ ___________________ (a) (a) . For . For
example, hydrochloric acid is used example, hydrochloric acid is used in toilet cleansers, caustic sodain toilet cleansers, caustic soda in oven cleansers and ammoniain oven cleansers and ammonia solution as window cleansers.solution as window cleansers.
cleansing agentscleansing agents
23 23 Acids & alkalisAcids & alkalis _____________ _____________ (a) (a)
each other in a chemical reaction each other in a chemical reaction
calledcalled ______________ ______________ (b)(b) . In . In
this reaction,this reaction, _____ _____ (c) (c) & ______ & ______ (d) (d)
are formed.are formed.
neutralizeneutralize
saltsalt waterwater
neutralizationneutralization
24 24 We can make use of neutralization We can make use of neutralization to solve many daily problems. to solve many daily problems. Examples areExamples are ::
> > Use ofUse of ___________ ___________ (a) (a) to treat to treat
stomach-achestomach-ache
> > Use of acids or alkalis to treat waUse of acids or alkalis to treat wa
sp, bee, mosquito & ant stingssp, bee, mosquito & ant stings
> > Neutralization of acidic & alkaline Neutralization of acidic & alkaline industrial wastes beforeindustrial wastes before
_________ _________ (b)(b)
antacidantacid
disposaldisposal
25 25 Acids & alkalis should be handled Acids & alkalis should be handled
carefully because they arecarefully because they are _______ _______
________ ________ (a) (a) ..corrosivecorrosive
10.710.7 10.710.7 Safety matters related to Safety matters related to the use of acids & alkalisthe use of acids & alkalis
26 26 ____________ ____________ (a) (a) acid is a solution tacid is a solution t
hat contains a high proportion of ahat contains a high proportion of a
cid in water.cid in water. _____________ _____________ (b) (b) alkali alkali
is a solution that contains a high pris a solution that contains a high pr
oportion of alkali in water. oportion of alkali in water. They are They are
much more ___________ much more ___________ c) c) than dilthan dil
ute acids ute acids & alkalis.& alkalis.
ConcentratedConcentrated
corrosivecorrosive
ConcentratedConcentrated
27 27 Concentrated acids and alkalis giv Concentrated acids and alkalis give out heat one out heat on __________ __________ (a) (a) . We m. We m
ust dilute concentrated acids & alkust dilute concentrated acids & alkalis by adding them to water, but nalis by adding them to water, but not by adding water to them. We muot by adding water to them. We must wear st wear protective clothes, safety gprotective clothes, safety goggles & gloves when doing so.oggles & gloves when doing so.
dilutiondilution
water
concentrated acid / alkali