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Chapter: 07. Air And Atmosphere

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The envelope of air around the earth is called the _ _ _ _ _ _ _ _ _ _ _ _ _ _.
atmosphere
Till the 18th century, people believed that air was just _ _ _ _ _ _ _ _ _ _ _ _ _ _.
one substance
In Lavoisier’s experiment, when mercury was heated over a charcoal furnace, a layer of red-coloured oxide of mercury was formed on the surface of the mercury in the _ _ _ _ _ _ _ _ _ _ _ _ _ _.
retort
Lavoisier initially named the remaining four-fifths of inactive air, which did not support burning or life, as _ _ _ _ _ _ _ _ _ _ _ _ _ _.
azote
Carbon dioxide reacts with limewater to turn it milky by forming an insoluble white solid substance called _ _ _ _ _ _ _ _ _ _ _ _ _ _.
calcium carbonate
Fine water droplets appear on the outer wall of a glass tumbler containing ice-cold water because water vapour in the air condenses on the _ _ _ _ _ _ _ _ _ _ _ _ _ _ of the tumbler.
cold surface
Nitrogen is the most abundant gas in the atmosphere, constituting about _ _ _ _ _ _ _ _ _ _ _ _ _ _ of air by volume.
78%
Potato chip packets are flushed with nitrogen gas before sealing to prevent the _ _ _ _ _ _ _ _ _ _ _ _ _ _ of food materials.
oxidation
Nitrogen is used to manufacture TNT, an explosive used to make bombs, where TNT stands for _ _ _ _ _ _ _ _ _ _ _ _ _ _.
trinitrotoluene
Free atmospheric nitrogen is converted into soluble nitrates by bacteria like _ _ _ _ _ _ _ _ _ _ _ _ _ _ present in the roots of leguminous plants.
Rhizobium
During nitrogen fixation by lightning, nitric acid reaches the soil through rain and reacts with metal carbonates to form metal _ _ _ _ _ _ _ _ _ _ _ _ _ _.
nitrates
The biological process where ammonium salt in the soil is converted first into nitrites and then into nitrates is called _ _ _ _ _ _ _ _ _ _ _ _ _ _.
nitrification
In 1774, Joseph Priestley prepared oxygen gas by focusing sunlight with a lens on mercuric oxide and named it _ _ _ _ _ _ _ _ _ _ _ _ _ _.
dephlogisticated air
The chemical formula of Epsom salt, which contains oxygen in a combined state, is _ _ _ _ _ _ _ _ _ _ _ _ _ _.
MgSO₄.7H₂O
During the fractional distillation of liquid air, nitrogen boils and separates at a temperature of _ _ _ _ _ _ _ _ _ _ _ _ _ _.
-195.5°C
In the laboratory preparation of oxygen gas, hydrogen peroxide is decomposed using _ _ _ _ _ _ _ _ _ _ _ _ _ _ as a catalyst.
manganese dioxide
Because oxygen is slightly soluble in water, it is collected in the laboratory using the process of _ _ _ _ _ _ _ _ _ _ _ _ _ _ of water.
downward displacement
When oxygen gas is passed through an alkaline pyrogallol solution, the solution turns _ _ _ _ _ _ _ _ _ _ _ _ _ _.
brown
Non-metals burn in oxygen to form non-metallic oxides that are _ _ _ _ _ _ _ _ _ _ _ _ _ _ in nature.
acidic
Phosphorus burns in oxygen with a dazzling flame and produces dense white fumes of _ _ _ _ _ _ _ _ _ _ _ _ _ _.
phosphorus pentoxide
Calcium burns in oxygen to form calcium oxide while producing a bright _ _ _ _ _ _ _ _ _ _ _ _ _ _ flame.
brick red
The slow oxidation process of iron in the presence of air and moisture produces hydrated ferric oxide, which is commonly known as _ _ _ _ _ _ _ _ _ _ _ _ _ _.
rust
Cutting and welding of metals are carried out using an oxyacetylene flame which is produced at a temperature of _ _ _ _ _ _ _ _ _ _ _ _ _ _.
3300°C
Solid carbon dioxide, which is used as a refrigerant for preserving perishable food items, is called _ _ _ _ _ _ _ _ _ _ _ _ _ _.
dry ice
The most abundant noble gas present in the atmosphere is _ _ _ _ _ _ _ _ _ _ _ _ _ _.
argon
The amount of water vapour present in the air is known as _ _ _ _ _ _ _ _ _ _ _ _ _ _.
humidity
The particles of mercury suspended in the air cause a severe disease called _ _ _ _ _ _ _ _ _ _ _ _ _ _.
Minamata
Acid rain corrodes and damages buildings, monuments, and statues made of _ _ _ _ _ _ _ _ _ _ _ _ _ _.
marble
Lead compounds released from automobile exhausts can cause brain damage, mental problems, and _ _ _ _ _ _ _ _ _ _ _ _ _ _.
paralysis
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