the atmosphere and air around us Flashcards

1
Q

what is an atmosphere?

A

the earth is surrounded by a thin layer of air called atmosphere

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2
Q

what is air?

A

Air is the mixture of several gases which have been physically combined together

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3
Q

name 2 main gases in air

A

nitrogen, oxygen

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4
Q

other gases that are present in smaller amounts of air are?

A

carbon dioxide, noble gases

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5
Q

3 main noble gases are?

A

argon, helium, neon

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6
Q

name all the 5 noble gases

A

argon helium neon krypton xenon

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7
Q

argon, neon, krypton and xenon are elements/molecules/compounds?

A

argon, neon, krypton and xenon are elements

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8
Q

nitrogen and oxygen are an elements/molecules/compounds?

A

nitrogen and oxygen are molecules. N2, O2

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9
Q

water vapor and carbon dioxide are elements/molecules/compounds?

A

water vapor and carbon dioxide are compounds

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10
Q

nitrogen percentage

A

78 %

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11
Q

oxygen percentage

A

21 %

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12
Q

carbon dioxide percentage

A

0.04 %

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13
Q

noble gases percentage

A

0.96 %

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14
Q

water vapor percentage

A

variable

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15
Q

define photosynthesis

A

photosynthesis is the process whereby a plant manufactures their own food

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16
Q

what happens during photosynthesis?

A

during photosynthesis, the chlorophyll present in the leaves trap in energy from sunlight to use it to convert water and carbon dioxide into oxygen and glucose .

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17
Q

what does the plant use to carry out photosynthesis?

A

sunlight, water, carbon dioxide and minerals from the soil

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18
Q

what energy does the glucose contain and what kind of change is photosynthesis?

A

the glucose contains chemical energy. the process of photosynthesis is an example of a chemical change, new products are formed and the change is irreversible

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19
Q

what is the product of photosynthesis?

A

the product of this process is food for the plant in form of glucose and oxygen gas

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20
Q

word equation of photosynthesis

A

carbon dioxide +
water
–chlorophyll
sunlight ———>
glucose + oxygen.

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21
Q

define respiration

A

respiration is a biochemical process during which organisms obtain energy

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22
Q

what happens during respiration?

A

during respiration, glucose is broken down in the presence of oxygen.

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23
Q

define combustion?

A

combustion is a chemical reaction between fuel and oxygen

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24
Q

what is complete combustion?

A

complete combustion is when fuel burns in sufficient amount of oxygen and forms water and carbon dioxide

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25
Q

what is in incomplete combustion?

A

incomplete combustion is when fuel is burned in insufficient amount of oxygen and forms carbon monoxide and water

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26
Q

what is carbon?

A

carbon is an element present in all living organisms

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27
Q

where is carbon present in other than living organisms?

A

it is present in air, rocks and soil

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28
Q

how is carbon returned in the atmosphere?

A

when fossil fuels are burnt carbon is returned in the atmosphere as carbon dioxide

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29
Q

define carbon cycle

A

the carbon cycle comprises of 3 processes namely, photosynthesis, combustion and respiration. (decomposition) these 3 processes maintain the level of carbon dioxide in the atmosphere almost constant.

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30
Q

define greenhouse gases

A

greenhouse gases are gases that retain heat energy in the atmosphere

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31
Q

define greenhouse effect

A

when greenhouse gasses retain an excess of heat energy in the atmosphere it is known as greenhouse effect

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32
Q

importance of greenhouse gases

A

they keep the earth’s surface warm for survival of human beings

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33
Q

the 2 main GHGs are?

A

methane and carbon dioxide

34
Q

what is methane and carbon dioxide responsible for?

A

they are the main cause of global warming

35
Q

name the activities that release methane

A

animal breeding and farming releases methane
decaying of wastes emits methane

36
Q

name the activities that release carbon dioxide

A

factories realease much carbon dioxide through their chimneys
when people burn garbage it produces carbon dioxide
badly maintained vehicles emit carbon dioxide in excess
deforestation contributes to emission of carbon dioxide

37
Q

how does deforestation cause emission of carbon dioxide

A

when trees are cut down and burnt, their stored carbon is released into the air as carbon dioxide

38
Q

define global warming

A

global warming is the increase of earth’s average temperature due to the presence of increasing amount of GHGs in the atmosphere

39
Q

how is global warming caused?

A

an increase of greenhouse gases retain excess heat energy in the atmosphere, resulting in global warming

40
Q

causes of global warming

A

production of electricity in power stations
burning of garbage
livestock farming
all means of transportation
decaying of organic wastes in landfills

41
Q

define climate change

A

climate change is the changes of weather patterns over time caused by increasing amounts of GHGs and other pollutants

42
Q

differentiate between climate change and global warming

A

global warming focuses on the increase of the earth’s average temperature due to increasing amounts of GHGs in the atmosphere
where as
climate change focuses on the changes of the weather pattern over time due to increasing amounts of GHGs and other air pollutants.

43
Q

examples of climate change

A

abnormal increase in temperature leading to severe drought
melting of glaciers
flooding and rising of sea levels
increase in frequency and intensity of cyclones
coral breaching
decreased rainfall

44
Q

what has led to climate change?

A

an increase in the amount of greenhouse gases and other pollutants has led to climate change

45
Q

measures to combat climate change

A

avoid burning of fossil fuels thus reducing the amount of carbon dioxide formed in the atmosphere
save electrical energy by using economic blubs
plant trees to absorb more carbon dioxide from the atmosphere
recycling of plastic waste
use alternate sources of energy like solar energy and wind energy

46
Q

name the air pollutants

A

carbon monoxide, oxides of nitrogen, sulfur dioxide, chlorofluorocarbon and smokes are considered air pollutants

47
Q

what is carbon monoxide?

A

carbon monoxide is a colourless and odourless gas

48
Q

how is carbon monoxide formed?

A

carbon monoxide is produced from incomplete combustion

49
Q

list a few examples of incomplete combustion

A

burning kerosene in a closed room (operating portable generators in a closed room)
using charcoal grills in a closed garage
operating gas water heaters in an enclosed bathroom with no proper ventilation
internal combustion engines of vehicles

50
Q

what are the effects of carbon monoxide ?

A

carbon monoxide is poisonous as it reduces oxygen transport by haemoglobin in the blood

51
Q

symptoms of carbon monoxide poisoning

A

headache, vomiting, loss of consciousness and death

52
Q

CO + HB ——> ?

A

CARBOXYHAEMOGLOBIN

53
Q

what is sulfur dioxide?

A

sulfur dioxide is a colourless gas with a sharp and irritating smell

54
Q

how is sulfur dioxide formed?

A

sulfur dioxide is formed when fossil fuels are burnt because fossil fuels contain sulfur which on combustion combines with oxygen to form sulfur dioxide

55
Q

list where sulfur dioxide is released

A

chimneys of factory burning fuels
(coal fired power stations)
exhaust pipes of motor vehicles

56
Q

where is sulfur dioxide naturally released?

A

during volcanic eruptions

57
Q

what are the effects of sulfur dioxide in the environment?

A

sulfur dioxide
reacts with water vapour and oxygen to form sulfuric acid,
this sulfuric acid then dissolves in clouds causing rain water to become acidic

58
Q

how is acid rain formed?

A

acid rain is formed when sulfur dioxide reacts with water vapour and oxygen to form sulfuric acid, this acid then dissolves in clouds making rain water acidic

59
Q

effects of sulfur dioxide in health

A

affects the respiratory system
causes coughing
aggravates conditions such as asthma and bronchitis
irritates eyes and skin as in dissolves in moisture to form acid

60
Q

name the oxides of nitrogen

A

nitrogen monoxide NO
nitrogen dioxide NO2

61
Q

how is oxides of nitrogen formed ?

A

oxides of nitrogen comes mostly from internal combustion engines of vehicles where oxygen and nitrogen from the air react at high temperatures prevailing in the engines

oxides of nitrogen also form during lightning

62
Q

How is lightning formed by oxides of nitrogen ?

A

the very high temperature in the vicinity of a lightning bolt causes

oxygen and nitrogen in the air to react and form oxides of nitrogen

63
Q

what are the effects of oxides of nitrogen in the environment ?

A

oxides of nitrogen react with water vapour and oxygen in the air to form nitric acid, thus causing acid rain

64
Q

what are the effects of oxides of nitrogen on health ?

A

they damage the lungs and cause respiratory problems
they irritate the eyes and skin
detrimental effect on human health

65
Q

what is smoke ?

A

smoke is an unwanted by-product of fires

66
Q

what does smoke consist of ?

A

it consists of tiny suspended solid particles which is mainly composed of soot and ash

67
Q

what poisonous gases does smoke contain ?

A

it contains carbon monoxide and acidic gases (sulfur dioxide and oxides of nitrogen)

68
Q

list sources of smoke

A

chimneys of factories
burning of garbage
burning of cigarette
exhaust pipes of vehicles
barbecue grills
spreading fire

69
Q

what are effects of smoke on the health ?

A

reduced oxygen content causing suffocation
smoke contains carbon monoxide which leads to headache loss of consciousness and death
smoke contains acidic gases like sulfur dioxide and oxides of nitrogen which causes irritation of eyes, skin burns and damage of the lungs

70
Q

what is chlorofluorocarbon CFC ?

A

chlorofluorocarbons are compounds which are made up of Carbon, Fluorine and chlorine.

71
Q

where are chlorofluorocarbons used ?

A

they are used as coolants in refrigerators and air conditioner
propellants for aerosols, cans (sprays)
cleaning agents since they remove grease and dirt

72
Q

name the layer that surrounds the earth’s atmosphere and give its function.

A

the layer surrounding the earth’s atmosphere is called the ozone layer and it helps to absorb Ultraviolet (UV) rays from the sun, preventing them from entering the atmosphere

73
Q

why is ultraviolet rays harmful ?

A

ultraviolet rays causes skin diseases, skin cancers and eye diseases (cataract)

74
Q

how is the ozone layer depleted ?

A

CFCs (Chlorofluorocarbon) break down in the upper atmosphere to form chlorine atoms which react with ozone layer thus depleting and making holes in it

75
Q

what are the effects of Ultraviolet rays ?

A

UV rays from the sun enter the atmosphere and increase the risk of skin cancers and eye diseases

76
Q

measures to prevent air pollution

A

sulfur dioxide from wastes gases of factories can be removed by passing the waste gases through powdered calcium carbonate (limestones)

catalytic convertors are devices which are found in exhaust systems, they convert harmful gasses into less harmful ones. carbon monoxide is converted into carbon dioxide and oxides of nitrogen is converted into nitrogen

people should be encouraged to use public transportation and to make use of carpooling in order to reduce the amount of fossil fuel burnt
CFCs should be replaced by other substances which do not deplete the ozone layer

burning waste at home should be avoided as it produces a lot of smoke and toxic gases

reguglar servicing of vehicles should be done to prevent emission of large amounts of smoke

filters should be placed on factory chimneys

spraying water around stone crushing plants

avoid spraying pesticides and insecticides on windy days

use renewable sources of energy

77
Q

what sectors mostly cause much air pollution ?

A

construction, agriculture, transport sectors cause much air pollution

78
Q

what is water pollution ?

A

water pollution id the discharge of harmful substances directly discharged or indirectly discharged into lakes, streams, rivers and oceans

79
Q

causes of water pollution

A

sewage from households, offices and industries
fertilisers from agriculture
industrial wastes
oil spillage from ships
garbage dumping

80
Q

what is eutrophication?

A

when excess of fertilizers is washed into lakes or river it increases the growth if algae thus covering the surface of the water, this prevents sunlight from reaching aquatic plants, then plants die and decompose depleting the oxygen in the water, consequently fish and other aquatic animals die