a density bottle weighs 70g when empty 90g when filled with water and 94g when filled with liquid x. find the density of liquix given that the density of water is 1000kg/m3
in using the lift pump to raise water from a borehole.it is observed that practically the height the water is raised cannot be 10m and more. Give reasons for this observations
A pin was observed to float on the surface of pure water. state two adjustments to the set up that may be made to cause the pin to sink other than shaking the container
when a bunsen burner is lit below wire gauze, it is noted that the flame initially burns below the gauze. Explain why after sometimes the flame burns below as well as above the gauze
A student was given a tube and a string. Describe how he will use them to determine the diameter of a test tube
Give a reason why ink is most likely to used out of a pen when one is up in an aeroplane
The reason why ink is most likely to be used out of a pen when one is up in an aeroplane is due to the change in air pressure and altitude. As an airplane ascends into the air, the atmospheric pressure decreases significantly. At cruising altitude, the pressure inside the cabin can be as low as 75% lower than at sea level.
Pens contain ink, which is a liquid that is normally held inside the pen by a combination of gravity and capillary action. When the air pressure outside the pen drops, the air inside the pen expands and pushes the ink towards the tip of the pen. At the same time, the decrease in air pressure outside the pen means that the ink is less likely to flow smoothly out of the pen, since there is less pressure to push it through the narrow opening in the pen tip.
This combination of factors can lead to ink being used up more quickly in a pen when one is up in an aeroplane. The ink may be pushed out of the pen more easily due to the lower air pressure inside, and it may be used up more quickly due to the difficulty of getting it to flow smoothly out of the pen tip. Additionally, the lower humidity inside the cabin can cause the ink to dry out faster, which may also contribute to the pen running out of ink more quickly.
The height of a mountain is 1360m. The barometer reading at the base of the mountain is 74cm of mercury. Given that the densities of mercury and air are 13600kg/m3 and 1.25kg/m3 respectively, determine the barometer reading at the top of the mountain
The volume of the bottle can be found by subtracting the weight of the empty bottle from the weight of the bottle filled with water:
Volume = (90g - 70g) / 1000kg/m^3 = 0.02 m^3
Let the density of liquid x be represented by ρx.
When the bottle is filled with liquid x, the weight of the liquid is 94g - 70g = 24g.
Using the formula for density, we can write:
ρx = mass/volume = 24g / 0.02 m^3 = 1200 kg/m^3
Therefore, the density of liquid x is 1200 kg/m^3.
The observations that a lift pump cannot practically raise water to a height of 10m or more are due to the following reasons:
1. Atmospheric pressure: The lift pump works by creating a vacuum that lifts the water up the pipe. However, the maximum height a pump can lift water is limited by atmospheric pressure. At sea level, atmospheric pressure is 1 atmosphere (atm) or 14.7 pounds per square inch (psi), which limits the maximum height to about 10.3m. As the altitude increases, atmospheric pressure decreases, so the maximum height decreases proportionally.
2. Friction losses: The lift pump may experience friction losses due to the drag of the water flow against the walls of the pipe, as well as flow resistance in the pump itself. As the height increases, the pressure required to overcome frictional losses also increases, making it harder for the pump to lift the water to a higher height.
3. Pump performance: The efficiency of the lift pump decreases as the height increases. Therefore, the pump may not have enough power to lift the water higher as it approaches its maximum capacity.
4. Cavitation: If the pressure in the pipe drops below the boiling point of the water, cavitation may occur, leading to damage to the pump and reducing its ability to lift water to a greater height.
In summary, the maximum height that a lift pump can practically raise water is limited by atmospheric pressure, frictional losses, pump performance, and cavitation.
If a pin is observed to float on the surface of pure water, there are two adjustments to the setup that can be made to cause the pin to sink without shaking the container:
1. Adding a surfactant: A surfactant is a substance that reduces the surface tension of water and makes it easier for objects to sink. Adding a small amount of a surfactant like soap or detergent to the water can reduce the surface tension and cause the pin to sink.
2. Increasing the weight of the pin: The gravity pulling the pin down into the water can be increased by attaching a small weight to the bottom of the pin. This will make the pin heavier and able to overcome the surface tension of the water. Alternatively, the pin can be replaced with a heavier object, like a paperclip, which will also be able to overcome the surface tension and sink in the water.
When a Bunsen burner is lit below a wire gauze, the flame initially burns below the gauze due to the air coming from the base of the burner. The air intake is open and allows air to mix with the gas as it is released from the burner. Thia creates a flame that is mostly yellow and smoky.
However, after some time, the flame begins to burn both below and above the wire gauze. This is due to the cooling effect of the gauze on the flame. As the flame heats the wire gauze, it loses energy and some of its heat. This decrease in temperature and energy causes the gas to burn less efficiently and produce less heat.
The wire gauze also acts as a catalyst for the reaction between the gas and oxygen in the air. As the gas is forced through the narrow holes in the gauze, it comes into contact with oxygen and reacts to produce a hotter, bluer flame on the top of the gauze. This reaction is much more efficient and produces more heat, allowing the flame to burn both below and above the wire gauze.
In summary, the wire gauze initially cools the flame and makes it less efficient, but also acts as a catalyst for a more efficient reaction that produces a hotter, bluer flame on the top of the gauze. This allows the flame to burn both below and above the wire gauze after some time.
To use a tube and a string to determine the diameter of a test tube, the student can follow these steps:
1. Cut a length of string that is longer than the circumference of the test tube. The string should be long enough to wrap around the test tube at least once with some extra length left over.
2. Hold one end of the string at one point on the test tube and gently wrap the string around the tube until it overlaps with the other end of the string. Make sure the string is wrapped loosely and does not squeeze or deform the shape of the tube.
3. Mark the point on the string where it overlaps with the other end. This point represents the circumference of the test tube.
4. Remove the string from the test tube and measure the distance between the two marks on the string. This distance is equal to the circumference of the test tube.
5. Divide the circumference by pi (3.14) to obtain the diameter. The formula for circumference is C = pi × D, where C is the circumference and D is the diameter. Therefore, D = C / pi.
In summary, by wrapping the string around the test tube and measuring the distance between the two marks, the student can determine the circumference of the test tube. Dividing this value by pi will give the diameter of the test tube.
The barometric pressure decreases as the altitude increases, due to the decrease in air density with increasing height. To determine the barometer reading at the top of the mountain, we can use the following formula:
P = ρgh
where P is the pressure, ρ is the density of the fluid (mercury) and g is the gravitational acceleration. h is the height difference between the two pressure measurements.
First, we need to find the height difference between the base and the top of the mountain:
h = 1360m
Next, we can calculate the pressure at the base of the mountain:
P1 = ρgh = (13600 kg/m^3)(9.81 m/s^2)(0.74 m) = 96108 Pa
where the density of mercury is 13600 kg/m^3, and 0.74m is the conversion of 74cm of mercury to meters.
To find the pressure at the top of the mountain, we can use the same formula:
P2 = ρgh = (1.25 kg/m^3)(9.81 m/s^2)(1360 m) = 16815 Pa
Therefore, the barometer reading at the top of the mountain would be:
P2 = 16815 Pa
When converting back to cm of mercury, this pressure is equivalent to:
P2 = (16815 Pa) / (133.32 Pa/cm Hg) = 126.15 cm of mercury
So, the barometer reading at the top of the mountain is approximately 126.15 cm of mercury.