Ch.9.4 Flashcards
Acid reacts with some metals (eg ___________________). During the reaction, a ________________ and ________________ are produced.
magnesium, salt, hydrogen
HYDROGEN FACT FILE 👐
—Hydrogen is a ________________ gas.
—How do we test for hydrogen?
colourless;
we can use a burning splint to test for hydrogen. when the burning splint is placed over a test tube containing hydrogen, the hydrogen burns with a ‘pop’ sound
When metal reacts with acid, ________________________________________________. We say that the acid ________________ the metal.
its size decreases slightly, corrodes
Name the metals in the: most reactive (1st tier) 2nd tier 3rd tier least reactive (4th tier) AND describe their reaction with acids.
1st — potassium, sodium — explosive reaction
2nd — magnesium, aluminium, zinc, iron — reacts with dilute acid, more slowly down the series
3rd — lead — very slow reaction
4th — copper, mercury, silver, gold — no reaction
What is the word equation for the reactions between acid and metals?
acid + metal —> salt + hydrogen
hydrochloric acid + magnesium —> ??
magnesium chloride + hydrogen
hydrochloric acid + aluminium —> ??
aluminium chloride + hydrogen
sulphuric acid + magnesium —> ??
magnesium sulphate + hydrogen
sulphuric acid + aluminium —> ??
aluminium sulphate + hydrogen
Besides reacting with metals, acids also react with _______________________________. Many ________________ ________________ contain this substance.
calcium carbonate, building materials
Give two examples of buildings made mainly of substances containing calcium carbonate.
The Kowloon Masjid and Islamic Centre in Hong Kong — marble
The Great Pyramid of Giza in Egypt — limestone
________________ and ________________ both contain calcium, which reacts with ________________ to produce a ________________, ________________ ________________ and ________________.
Marble, limestone, acids, salt, carbon dioxide, water
CARBON DIOXIDE FACT FILE 👐
—Carbon dioxide is a ________________ gas
—When carbon dioxide is mixed with ________________, it ________________________________________________.
colourless, limewater, turns the limewater milky
Some building structures such as ________________ ___________ and ___________________ are made of marble. We should avoid ________________________________________________________________ _______________________________________________.
kitchen tops, windowsills, using acidic cleaners to clean marble surfaces as acids will corrode the material
Apart from marble and limestone, some substances such as ________________, ________________ and ________________ also contain calcium carbonate. They will be ______________________ by acids.
pearls, seashells, eggshells, corroded
What is the word equation for reactions between acids and carbonates?
acid + carbonate —> salt + carbon dioxide + water
hydrochloric acid + calcium carbonate —> ??
calcium chloride + carbon dioxide + water
sulphuric acid + calcium carbonate —> ??
calcium sulphate + carbon dioxide + water
nitric acid + calcium carbonate —>
calcium nitrate + carbon dioxide + water
Rainwater is naturally ________________ ________________ and has a pH value of about ___________. If the rainwater is more acidic than it should be, it is considered to be _____________ _____________.
slightly acidic, 5.6, acid rain
________________ ________________ are the main cause of acid rain. Over the past two centuries, _________________________________________________________________________________________________________________________________________. This releases a lot of ________________ ________________ including ________________ ________________ and ________________ ________________, which are ________________ gases.
Human activities.
more and more fossil fuels have been burned in power stations, factories and vehicles
air pollutants, sulphur dioxide, nitrogen oxide, acidic
What are the three steps of the formation of acid rain?
1.
2.
3.
- Acidic gases such as sulphur dioxide and nitrogen oxides are released into the atmosphere
- They dissolve in water droplets and then sulphuric acid and nitric acid are produced respectively
- These acidic droplets later join to form clouds and fall as acid rain
What are the sources and types of acidic gases that cause the formation of acid rain? sources: — — — types: — —
—Power stations (sulphur dioxide) —Factories (sulphur dioxide) —Vehicles (nitrogen oxide) ; —sulphur dioxide —nitrogen oxides
Fossil fuels contain some ________________ ________________. The burning of fossil fuels causes ________________ to react with ________________ producing ________________ ________________.
sulphur impurities, sulphur, oxygen, sulphur dioxide
What are the three effects of acid rain on the environment and living things?
1.
2.
3.
- Corroding metal objects and building materials
- Damaging plants
- Causing harm to aquatic life
Why is acid rain a problem for everyone?
This is because acidic gases (eg sulphur dioxide and nitrogen oxides) may be spread by wind over long distances, causing damage not only to the place where the acidic gases come from.
Elaborate on how acid rain corrodes metal objects and building materials.
—
—
—
Acid rain corrodes metal objects such as iron fences, bridges and motor car bodies
It also corrodes building materials and statues made of metal or marble.
Elaborate on how acid rain damages plants. — — — — — —
—Acid rain may destroy the leaves of plant directly, especially high-altitude forests.
—The plants die if they cannot carry out photosynthesis (due to the lack of leaves).
—Acid rain also dissolves and washes away the nutrients in the soil
—As a result, the plants cannot get enough nutrients for growth; They may grow slowly or even die.
—Acid rain also increases the acidity of soil
—Many plants cannot grow well in acidic soil
Elaborate on how acid rain causes harm to aquatic life. — — — — —
—If acid rain enters lakes and rivers, it increases the acidity of water
—Most aquatic life cannot survive in water which is too acidic
—Low pH levels kill fishes, their eggs and food organisms
—Acid rain also dissolves minerals in the soil, washes them out of the soil and carries them into the rivers and lakes
—Some of these minerals are harmful and may slow down the growth and reproduction of aquatic life
Conclude how acid rain is formed.
Acid rain is formed when acidic gases like sulphur dioxide and nitrogen oxides dissolve in rainwater.
Name one natural cause of acid rain.
Erupting volcanoes emit sulphur dioxide.
Why do statues made of marble turn yellow in colour?
This is because acid in the air reacts with calcium carbonate of marble.
