36 questions
Translate the following statements into chemical equations and then balance them.
Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
2K + 2H2O → 2KOH + H2
3BaCl2 + Al2(SO4)3 → 2AlCl3 + 3BaSO4
2H2S + 3O2 → 2H2O + 2SO2
3H2 + N2 → 2NH3
Translate the following statements into chemical equations and then balance them.
Hydrogen sulphide gas burns in air to give water and sulphur dioxide
2K + 2H2O → 2KOH + H2
3BaCl2 + Al2(SO4)3 → 2AlCl3 + 3BaSO4
2H2S + 3O2 → 2H2O + 2SO2
3H2 + N2 → 2NH3
Translate the following statements into chemical equations and then balance them.
Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
2K + 2H2O → 2KOH + H2
3BaCl2 + Al2(SO4)3 → 2AlCl3 + 3BaSO4
2H2S + 3O2 → 2H2O + 2SO2
3H2 + N2 → 2NH3
Translate the following statements into chemical equations and then balance them.
Methane burns in oxygen to form CO2 and water. Write a balanced equation for the reaction
2K + 2H2O → 2KOH + H2
3BaCl2 + Al2(SO4)3 → 2AlCl3 + 3BaSO4
2H2S + 3O2 → 2H2O + 2SO2
CH4+2O2→CO2+2H2O.
Identify the reducing agent in the following reactions
4NH3 + 5O2 → 4NO + 6H2O
Ammonia (NH3) is the reducing agent, it has reduced O2 which acts as an oxidising agent.
Water (H2O) is the reducing agent. It has reducedF2 which acts as an oxidising agent.
Carbon monoxide (CO) is the reducing agent, it has reduced ferric oxide (Fe2O3) which acts as an oxidising agent.
Hydrogen (H2) is the reducing agent, it has reduced oxygen (O2) which acts as an oxidising agent.
Identify the reducing agent in the following reactions
H2O + F2 → HF + HOF
Ammonia (NH3) is the reducing agent, it has reduced O2 which acts as an oxidising agent.
Water (H2O) is the reducing agent. It has reducedF2 which acts as an oxidising agent.
Carbon monoxide (CO) is the reducing agent, it has reduced ferric oxide (Fe2O3) which acts as an oxidising agent.
Hydrogen (H2) is the reducing agent, it has reduced oxygen (O2) which acts as an oxidising agent.
Identify the reducing agent in the following reactions
Fe2O3 + 3CO → 2Fe + 3CO2
Ammonia (NH3) is the reducing agent, it has reduced O2 which acts as an oxidising agent.
Water (H2O) is the reducing agent. It has reducedF2 which acts as an oxidising agent.
Carbon monoxide (CO) is the reducing agent, it has reduced ferric oxide (Fe2O3) which acts as an oxidising agent.
Hydrogen (H2) is the reducing agent, it has reduced oxygen (O2) which acts as an oxidising agent.
Identify the reducing agent in the following reactions
2H2 + O2 → 2H2O
Ammonia (NH3) is the reducing agent, it has reduced O2 which acts as an oxidising agent.
Water (H2O) is the reducing agent. It has reducedF2 which acts as an oxidising agent.
Carbon monoxide (CO) is the reducing agent, it has reduced ferric oxide (Fe2O3) which acts as an oxidising agent.
Hydrogen (H2) is the reducing agent, it has reduced oxygen (O2) which acts as an oxidising agent.
The structural formula of Ethyne
Define 'refractive index of a transparent medium'. What is its unit? Which one has a higher refractive index, glass or water? What is the first statement of the audio clip?
Refractive index of transparent medium is defined as the ratio of speed of light in vacuum to the speed of light through medium.
That is, Refractive index, n=c/v. Where, Speed of light = c Speed of light in medium = v
It has no unit because it is a ratio of two quantities of same type (speed).
Glass has higher refractive index (1.52) than water, because refractive index of water is 1.33.
Define 'refractive index of a transparent medium'. What is its unit? Which one has a higher refractive index, glass or water? What is the first statement of the audio clip?
Refractive index of transparent medium is defined as the ratio of speed of light in vacuum to the speed of light through medium.
That is, Refractive index, n=c/v. Where, Speed of light = c Speed of light in medium = v
It has no unit because it is a ratio of two quantities of same type (speed).
Glass has higher refractive index (1.52) than water, because refractive index of water is 1.33.
Define 'refractive index of a transparent medium'. What is its unit? Which one has a higher refractive index, glass or water? What is the Third statement of the audio clip?
Refractive index of transparent medium is defined as the ratio of speed of light in vacuum to the speed of light through medium.
That is, Refractive index, n=c/v. Where, Speed of light = c Speed of light in medium = v
It has no unit because it is a ratio of two quantities of same type (speed).
Glass has higher refractive index (1.52) than water, because refractive index of water is 1.33.
Define 'refractive index of a transparent medium'. What is its unit? Which one has a higher refractive index, glass or water? What is the Fourth statement of the audio clip?
Refractive index of transparent medium is defined as the ratio of speed of light in vacuum to the speed of light through medium.
That is, Refractive index, n=c/v. Where, Speed of light = c Speed of light in medium = v
It has no unit because it is a ratio of two quantities of same type (speed).
Glass has higher refractive index (1.52) than water, because refractive index of water is 1.33.
Uses of Bleaching powder. What is the first statement of the clip?
It is used for several purposes:
As a bleaching agent for bleaching cotton and linen in the textile industry,
To bleach wood pulp in paper manufacturing industry.
To bleach washed clothes in laundry.
As an oxidising agent in many chemical industries.
To disinfect drinking water and make it germfree.
Uses of Bleaching powder. What is the Second statement of the clip?
It is used for several purposes:
As a bleaching agent for bleaching cotton and linen in the textile industry,
To bleach wood pulp in paper manufacturing industry.
To bleach washed clothes in laundry.
As an oxidising agent in many chemical industries.
To disinfect drinking water and make it germfree.
Uses of Bleaching powder. What is the Third statement of the clip?
It is used for several purposes:
As a bleaching agent for bleaching cotton and linen in the textile industry,
To bleach wood pulp in paper manufacturing industry.
To bleach washed clothes in laundry.
As an oxidising agent in many chemical industries.
To disinfect drinking water and make it germfree.
Uses of Bleaching powder. What is the Fourth statement of the clip?
It is used for several purposes:
As a bleaching agent for bleaching cotton and linen in the textile industry,
To bleach wood pulp in paper manufacturing industry.
To bleach washed clothes in laundry.
As an oxidising agent in many chemical industries.
To disinfect drinking water and make it germfree.
Uses of Bleaching powder. What is the Fifth statement of the clip?
It is used for several purposes:
As a bleaching agent for bleaching cotton and linen in the textile industry,
To bleach wood pulp in paper manufacturing industry.
To bleach washed clothes in laundry.
As an oxidising agent in many chemical industries.
To disinfect drinking water and make it germfree.
What are acids? What is the first statement of the audio clip?
Acids
Acids taste sour – in fact, the German word for acid is sauer.
Because acids can damage cells, our stomach needs a special lining to protect it from the hydrochloric acid used to digest our food.
We are familiar with some acids – citrus fruits, tomatoes and vinegar are acidic
Acids react with most metals including magnesium to create hydrogen gas and a salt – there are lots of different types of salts in chemistry
They also react with a group of substances called carbonates to produce carbon dioxide
gas, salt and water.
What are acids? What is the Second statement of the audio clip?
Acids
Acids taste sour – in fact, the German word for acid is sauer.
Because acids can damage cells, our stomach needs a special lining to protect it from the hydrochloric acid used to digest our food.
We are familiar with some acids – citrus fruits, tomatoes and vinegar are acidic
Acids react with most metals including magnesium to create hydrogen gas and a salt – there are lots of different types of salts in chemistry
They also react with a group of substances called carbonates to produce carbon dioxide
gas, salt and water.
What are acids? What is the Third statement of the audio clip?
Acids
Acids taste sour – in fact, the German word for acid is sauer.
Because acids can damage cells, our stomach needs a special lining to protect it from the hydrochloric acid used to digest our food.
We are familiar with some acids – citrus fruits, tomatoes and vinegar are acidic
Acids react with most metals including magnesium to create hydrogen gas and a salt – there are lots of different types of salts in chemistry
They also react with a group of substances called carbonates to produce carbon dioxide
gas, salt and water.
What are acids? What is the Fourth statement of the audio clip?
Acids
Acids taste sour – in fact, the German word for acid is sauer.
Because acids can damage cells, our stomach needs a special lining to protect it from the hydrochloric acid used to digest our food.
We are familiar with some acids – citrus fruits, tomatoes and vinegar are acidic
Acids react with most metals including magnesium to create hydrogen gas and a salt – there are lots of different types of salts in chemistry
They also react with a group of substances called carbonates to produce carbon dioxide
gas, salt and water.
What are acids? What is the Fifth statement of the audio clip?
Acids
Acids taste sour – in fact, the German word for acid is sauer.
Because acids can damage cells, our stomach needs a special lining to protect it from the hydrochloric acid used to digest our food.
We are familiar with some acids – citrus fruits, tomatoes and vinegar are acidic
Acids react with most metals including magnesium to create hydrogen gas and a salt – there are lots of different types of salts in chemistry
They also react with a group of substances called carbonates to produce carbon dioxide
gas, salt and water.
1KWh contains 3.6×10^6 Joules
True
False
We often see the sun briefly before it actually rises above the horizon and for a few minutes after it sets below the horizon. This phenomenon, known as atmospheric refraction, occurs due to the Earth's atmosphere.
Imagine the Earth as a sphere and yourself standing on its surface. The horizon is the imaginary line where the sky and the Earth seem to meet. When the sun is truly above the horizon, its light reaches your eyes directly, and you can see it clearly.
However, when the sun is just below the horizon, its light doesn't travel in a straight line. As it enters Earth's atmosphere, the light bends slightly towards the denser layers closer to the ground. This bending, caused by refraction, makes the sun appear higher in the sky than it actually is.
Therefore, you see the sun two minutes earlier than when it actually crosses the horizon. This 'advance' in sunrise effectively extends the daylight period. Similarly, during sunset, when the sun is truly below the horizon, the light still bends as it enters the atmosphere.
Why do we see the sun briefly before it rises and after it sets?
Due to atmospheric refraction
Because the Earth rotates faster at the equator
As a result of gravitational pull from the moon
Because of changes in the Earth's magnetic field
How does the 'advance' in sunrise effectively extend the daylight period?
During sunset, the bending of light still occurs as the sun enters the atmosphere. The bending of light is also known as ___
Why do we see the sun two minutes earlier than its actual sunrise time?
Due to the bending of light
Because of the Earth's rotation
As a result of atmospheric refraction
By the effect of gravitational pull
Why does the sun appear higher in the sky than it actually is?
Due to the Earth's atmosphere bending the sun's light
Because of the sun's natural position
As a result of the moon's gravitational pull
From the reflection off of other planets
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We often see the sun briefly before it actually rises above the horizon and for a few minutes after it sets below the horizon. This phenomenon, known as atmospheric refraction, occurs due to the Earth's atmosphere.
Imagine the Earth as a sphere and yourself standing on its surface. The horizon is the imaginary line where the sky and the Earth seem to meet. When the sun is truly above the horizon, its light reaches your eyes directly, and you can see it clearly.
However, when the sun is just below the horizon, its light doesn't travel in a straight line. As it enters Earth's atmosphere, the light bends slightly towards the denser layers closer to the ground. This bending, caused by refraction, makes the sun appear higher in the sky than it actually is.
Therefore, you see the sun two minutes earlier than when it actually crosses the horizon. This "advance" in sunrise effectively extends the daylight period.
Similarly, during sunset, when the sun is truly below the horizon, the light still bends as it enters the atmosphere. This creates the illusion that the sun is higher than it actually is, allowing you to see it for two minutes longer after it has dipped below the horizon. This "delay" in sunset essentially extends the twilight period.
In summary, atmospheric refraction bends sunlight as it enters the Earth's atmosphere, creating an optical illusion that allows us to see the sun slightly earlier during sunrise and slightly later during sunset. This phenomenon effectively extends both daylight and twilight periods by about two minutes each.
How does the phenomenon of seeing the sun before and after its true position enhance our experience of sunrise and sunset?
It creates a sense of anticipation and beauty.
It causes confusion and disorientation.
It has no effect on our experience.
It makes the sun appear larger in the sky.
How does the Earth's atmosphere contribute to bending sunlight and creating visual effects?
By reflecting sunlight off its surface
By absorbing sunlight and emitting it as heat
By scattering sunlight in different directions
By generating its own light
How does understanding atmospheric refraction help explain why we perceive the sun's position differently?
It affects the speed at which the sun appears to move across the sky
It causes the sun to appear larger or smaller than it actually is
It alters the angle at which sunlight reaches our eyes
It creates the illusion of the sun rising and setting at different times
Why does the sun appear higher in the sky when it is just below the horizon?
Due to refraction of light
Due to reflection of light
Due to diffraction of light
Due to absorption of light
What causes us to see the sun earlier and later than actual sunrise and sunset?
Atmospheric refraction
Light pollution
Global warming
Solar flares
Why do we see the sun two minutes earlier during sunrise and two minutes longer after sunset?
Due to refraction
Due to rotation of the Earth
Due to the moon's gravitational pull
Due to cloud cover
How much does the optical illusion extend both daylight and twilight periods by?
One minute each
Two minutes each
Three minutes each
Four minutes each