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### Question 3: State two factors that would raise the boiling point of water.
Two factors that would raise the boiling point of water are:
1. Increased Atmospheric Pressure:
- When the atmospheric pressure is increased, the boiling point of water goes up. This is because water molecules need more energy to escape into the vapor phase against the higher pressure.
- Example: Water boils at a higher temperature in a pressure cooker.
2. Presence of Solutes (Impurities):
- Adding a non-volatile solute (such as salt) to water will raise its boiling point. This is known as boiling point elevation, a colligative property of solutions.
- Example: Seawater boils at a higher temperature than pure water.
### Question 4: The level of water in a burette is 2.5 cm³. 40 drops each of volume 0.05 cm³ are added. What would be its new reading?
To find the new reading in the burette, follow these steps:
1. Initial Level of Water:
- The initial level of water in the burette is given as 2.5 cm³.
2. Volume of Each Drop:
- Each drop has a volume of 0.05 cm³.
3. Number of Drops Added:
- There are 40 drops added to the burette.
4. Calculate Total Volume Added:
- Total volume added by drops = Volume of each drop × Number of drops
- Total volume added = 0.05 cm³/drop × 40 drops = 2.0 cm³
5. Calculate the New Reading:
- New reading in the burette = Initial level of water + Total volume added
- New reading = 2.5 cm³ + 2.0 cm³ = 4.5 cm³
Answer: The new reading in the burette is 4.5 cm³.
### Question F: A lorry is brought to rest from 200 km/h in 30 seconds. Calculate the acceleration.
To calculate the acceleration, follow these steps:
1. Convert the Initial Speed to m/s:
- Initial speed = 200 km/h
- Convert km/h to m/s: [tex]\( 1 \text{ km/h} = \frac{1 \times 1000 \text{ m}}{3600 \text{ s}} \)[/tex]
- Initial speed in m/s = [tex]\( 200 \text{ km/h} \times \frac{1000 \text{ m}}{3600 \text{ s}} = \frac{200 \times 1000}{3600} \text{ m/s} = \frac{200000}{3600} \text{ m/s} = \frac{500}{9} \text{ m/s} \approx 55.56 \text{ m/s} \)[/tex]
2. Final Speed:
- Since the lorry is brought to rest, the final speed (v) = 0 m/s.
3. Time Taken:
- The time taken to come to rest, t = 30 seconds.
4. Use the Formula for Acceleration:
- The formula to calculate acceleration (a) is: [tex]\( a = \frac{v - u}{t} \)[/tex]
- where [tex]\( v \)[/tex] is the final velocity, [tex]\( u \)[/tex] is the initial velocity, and [tex]\( t \)[/tex] is the time.
5. Substitute the Values:
- a = [tex]\( \frac{0 \text{ m/s} - 55.56 \text{ m/s}}{30 \text{ s}} \)[/tex]
6. Calculate the Acceleration:
- a = [tex]\( \frac{-55.56 \text{ m/s}}{30 \text{ s}} = -1.852 \text{ m/s}^2 \)[/tex]
Answer: The acceleration is [tex]\( -1.852 \text{ m/s}^2 \)[/tex]. The negative sign indicates that it is a deceleration.
### Question 3: State two factors that would raise the boiling point of water.
Two factors that would raise the boiling point of water are:
1. Increased Atmospheric Pressure:
- When the atmospheric pressure is increased, the boiling point of water goes up. This is because water molecules need more energy to escape into the vapor phase against the higher pressure.
- Example: Water boils at a higher temperature in a pressure cooker.
2. Presence of Solutes (Impurities):
- Adding a non-volatile solute (such as salt) to water will raise its boiling point. This is known as boiling point elevation, a colligative property of solutions.
- Example: Seawater boils at a higher temperature than pure water.
### Question 4: The level of water in a burette is 2.5 cm³. 40 drops each of volume 0.05 cm³ are added. What would be its new reading?
To find the new reading in the burette, follow these steps:
1. Initial Level of Water:
- The initial level of water in the burette is given as 2.5 cm³.
2. Volume of Each Drop:
- Each drop has a volume of 0.05 cm³.
3. Number of Drops Added:
- There are 40 drops added to the burette.
4. Calculate Total Volume Added:
- Total volume added by drops = Volume of each drop × Number of drops
- Total volume added = 0.05 cm³/drop × 40 drops = 2.0 cm³
5. Calculate the New Reading:
- New reading in the burette = Initial level of water + Total volume added
- New reading = 2.5 cm³ + 2.0 cm³ = 4.5 cm³
Answer: The new reading in the burette is 4.5 cm³.
### Question F: A lorry is brought to rest from 200 km/h in 30 seconds. Calculate the acceleration.
To calculate the acceleration, follow these steps:
1. Convert the Initial Speed to m/s:
- Initial speed = 200 km/h
- Convert km/h to m/s: [tex]\( 1 \text{ km/h} = \frac{1 \times 1000 \text{ m}}{3600 \text{ s}} \)[/tex]
- Initial speed in m/s = [tex]\( 200 \text{ km/h} \times \frac{1000 \text{ m}}{3600 \text{ s}} = \frac{200 \times 1000}{3600} \text{ m/s} = \frac{200000}{3600} \text{ m/s} = \frac{500}{9} \text{ m/s} \approx 55.56 \text{ m/s} \)[/tex]
2. Final Speed:
- Since the lorry is brought to rest, the final speed (v) = 0 m/s.
3. Time Taken:
- The time taken to come to rest, t = 30 seconds.
4. Use the Formula for Acceleration:
- The formula to calculate acceleration (a) is: [tex]\( a = \frac{v - u}{t} \)[/tex]
- where [tex]\( v \)[/tex] is the final velocity, [tex]\( u \)[/tex] is the initial velocity, and [tex]\( t \)[/tex] is the time.
5. Substitute the Values:
- a = [tex]\( \frac{0 \text{ m/s} - 55.56 \text{ m/s}}{30 \text{ s}} \)[/tex]
6. Calculate the Acceleration:
- a = [tex]\( \frac{-55.56 \text{ m/s}}{30 \text{ s}} = -1.852 \text{ m/s}^2 \)[/tex]
Answer: The acceleration is [tex]\( -1.852 \text{ m/s}^2 \)[/tex]. The negative sign indicates that it is a deceleration.
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