Metals like copper and silver appear to be dull because of corrosion due to sulphur, carbon dioxide and moisture present in the atmosphere. Brightness of the metals can be restored by rubbing with a cloth moistened with a dilute acid.
Metals like copper and silver appear to be dull because of corrosion due to sulphur, carbon dioxide and moisture present in the atmosphere.
Brightness of the metals can be restored by rubbing with a cloth moistened with a dilute acid.
Power is said to be 1 watt if rate of supply of energy in an electrical circuit is 1 joule per second. Mathematically: 1 watt of power = 1 volt potential difference x 1 ampere current
Power is said to be 1 watt if rate of supply of energy in an electrical circuit is 1 joule per second.
Mathematically:
1 watt of power = 1 volt potential difference x 1 ampere current
Multicellular organisms like humans have large body size and hence diffusion pressure alone cannot carry oxygen to all body parts. Thus, they have respiratory pigment to take up oxygen from lungs to body parts.
Multicellular organisms like humans have large body size and hence diffusion pressure alone cannot carry oxygen to all body parts. Thus, they have respiratory pigment to take up oxygen from lungs to body parts.
Carbon dioxide gas is essential for photosynthesis by plants- It is also a green-house gas (GHG). Upto 350 ppm (ppm = parts per million) concentration in the-atmosphere, CO₂ is both a good raw material as well as essential for keeping the Earth warm. However, when concentration of Co₂ rises (as presRead more
Carbon dioxide gas is essential for photosynthesis by plants- It is also a green-house gas (GHG). Upto 350 ppm (ppm = parts per million) concentration in the-atmosphere, CO₂ is both a good raw material as well as essential for keeping the Earth warm. However, when concentration of Co₂ rises (as presently it is 387 ppm), it becomes a pollutant because it-results in global warming. The global warming is quite dangerous because it tends to melt polar ice and glaciers existing on mountains, raise in the water level of oceans and submerge severals coastal areas and islands.
sun plays an important role in weathering of rocks for soil formation. It heats up the rocks during the day. Heating causes the rocks to expand. During night, the rocks cool down and contract. Deferent parts of a rock expand and contract at different rates resulting in its cracking and breaking up iRead more
sun plays an important role in weathering of rocks for soil formation. It heats up the rocks during the day. Heating causes the rocks to expand. During night, the rocks cool down and contract. Deferent parts of a rock expand and contract at different rates resulting in its cracking and breaking up into smaller pieces or fragments (boulders).
(i) Dust consists of suspended particles. The latter pass into nasal tract and cause a lot of discomfort including allergic asthma, bronchitis, cough and cold (ii) Dust reduces light intensity (iii) Dust particles are eye irritants. (iv) Dust particles settle over plant foliage and reduce photosynthRead more
(i) Dust consists of suspended particles. The latter pass into nasal tract and cause a lot of discomfort including allergic asthma, bronchitis, cough and cold
(ii) Dust reduces light intensity
(iii) Dust particles are eye irritants.
(iv) Dust particles settle over plant foliage and reduce photosynthetic activity
(v) Dust particles block stomata reduces gaseous exchange in plants
(vi) Dust particles can pick up toxic metals and chemicals being emitted by industries
Glass is transparent to sunlight allowing it heat waves do not escape from the car due I car placed in the sun will become very hot. to pass into the interior of the car. It heats up the interior. But to glass being opaque to the same. As a result, the interior of the It is similar to glass house efRead more
Glass is transparent to sunlight allowing it heat waves do not escape from the car due I car placed in the sun will become very hot. to pass into the interior of the car. It heats up the interior. But to glass being opaque to the same. As a result, the interior of the It is similar to glass house effect.
Zinc oxide reacts with carbon, on heating to form zinc metal and carbon monoxide. Write a balanced chemical equation for this reaction. Name (i) the substance oxidised and (ii) the substance reduced.
ZnO + c ⟶ Zn + CO ZnO is reduced to zinc metal. C is oxidised to CO.
ZnO + c ⟶ Zn + CO
See lessZnO is reduced to zinc metal.
C is oxidised to CO.
Write the chemical name and formula of gypsum. What happens when gypsum is heated at 373 K? Write chemical equation for the reaction.
Chemical name: Calcium sulphate hydrated Formula: CaSO₄.2H₂O On heating gypsum at 373 K, gypsum changes to plaster of Paris. ∆ CaSO₄.2H₂O ⟶ CaSO₄.1/2 H₂O+ 3/2 H₂O 373k
Chemical name: Calcium sulphate hydrated
See lessFormula: CaSO₄.2H₂O
On heating gypsum at 373 K, gypsum changes to plaster of Paris.
∆
CaSO₄.2H₂O ⟶ CaSO₄.1/2 H₂O+ 3/2 H₂O
373k
Metals are said to be shiny. Why do metals generally appear to be dull? How can their brightness be restored?
Metals like copper and silver appear to be dull because of corrosion due to sulphur, carbon dioxide and moisture present in the atmosphere. Brightness of the metals can be restored by rubbing with a cloth moistened with a dilute acid.
Metals like copper and silver appear to be dull because of corrosion due to sulphur, carbon dioxide and moisture present in the atmosphere.
See lessBrightness of the metals can be restored by rubbing with a cloth moistened with a dilute acid.
Name any two conventional sources of energy.
Two conventional sources of energy are fossil fuels like coal, petroleum, etc., and the sun.
Two conventional sources of energy are fossil fuels like coal, petroleum, etc., and the sun.
See lessDefine 1 watt.
Power is said to be 1 watt if rate of supply of energy in an electrical circuit is 1 joule per second. Mathematically: 1 watt of power = 1 volt potential difference x 1 ampere current
Power is said to be 1 watt if rate of supply of energy in an electrical circuit is 1 joule per second.
See lessMathematically:
1 watt of power = 1 volt potential difference x 1 ampere current
Diffusion is insufficient to meet the oxygen requirements of multicellular organisms like human. State reason.
Multicellular organisms like humans have large body size and hence diffusion pressure alone cannot carry oxygen to all body parts. Thus, they have respiratory pigment to take up oxygen from lungs to body parts.
Multicellular organisms like humans have large body size and hence diffusion pressure alone cannot carry oxygen to all body parts. Thus, they have respiratory pigment to take up oxygen from lungs to body parts.
See lessCarbon dioxide is necessary for plants. Why do we consider it as a pollutant?
Carbon dioxide gas is essential for photosynthesis by plants- It is also a green-house gas (GHG). Upto 350 ppm (ppm = parts per million) concentration in the-atmosphere, CO₂ is both a good raw material as well as essential for keeping the Earth warm. However, when concentration of Co₂ rises (as presRead more
Carbon dioxide gas is essential for photosynthesis by plants- It is also a green-house gas (GHG). Upto 350 ppm (ppm = parts per million) concentration in the-atmosphere, CO₂ is both a good raw material as well as essential for keeping the Earth warm. However, when concentration of Co₂ rises (as presently it is 387 ppm), it becomes a pollutant because it-results in global warming. The global warming is quite dangerous because it tends to melt polar ice and glaciers existing on mountains, raise in the water level of oceans and submerge severals coastal areas and islands.
See lessExplain the role of the sun in the formation of soil.
sun plays an important role in weathering of rocks for soil formation. It heats up the rocks during the day. Heating causes the rocks to expand. During night, the rocks cool down and contract. Deferent parts of a rock expand and contract at different rates resulting in its cracking and breaking up iRead more
sun plays an important role in weathering of rocks for soil formation. It heats up the rocks during the day. Heating causes the rocks to expand. During night, the rocks cool down and contract. Deferent parts of a rock expand and contract at different rates resulting in its cracking and breaking up into smaller pieces or fragments (boulders).
See lessJustify “Dust is a pollutant”.
(i) Dust consists of suspended particles. The latter pass into nasal tract and cause a lot of discomfort including allergic asthma, bronchitis, cough and cold (ii) Dust reduces light intensity (iii) Dust particles are eye irritants. (iv) Dust particles settle over plant foliage and reduce photosynthRead more
(i) Dust consists of suspended particles. The latter pass into nasal tract and cause a lot of discomfort including allergic asthma, bronchitis, cough and cold
See less(ii) Dust reduces light intensity
(iii) Dust particles are eye irritants.
(iv) Dust particles settle over plant foliage and reduce photosynthetic activity
(v) Dust particles block stomata reduces gaseous exchange in plants
(vi) Dust particles can pick up toxic metals and chemicals being emitted by industries
A motor car with its, glass totally closed, is parked directly under the sun. The inside temperature of the car rises very high. Explain
Glass is transparent to sunlight allowing it heat waves do not escape from the car due I car placed in the sun will become very hot. to pass into the interior of the car. It heats up the interior. But to glass being opaque to the same. As a result, the interior of the It is similar to glass house efRead more
Glass is transparent to sunlight allowing it heat waves do not escape from the car due I car placed in the sun will become very hot. to pass into the interior of the car. It heats up the interior. But to glass being opaque to the same. As a result, the interior of the It is similar to glass house effect.
See less