can I get some help with these questions. im not sure on these ones
During the stage of internal combustion engine operation in which the piston rises and compresses the fuel in the combustion chamber,
a. both the intake and exhaust valves are open
b. the intake valve is open and the exhaust valve is closed
c. both the intake and exhaust valves are closed
d. the exhaust valve is open and the intake valve is closed
how much heat energy is required to raise the temperature of 5 kilograms of coal from 20*c to 220*c
a.1324718
b.4187000
c.6573
d.314
If any valves were open, you could not compress the gas.
5 KG * specific heat of coal * 200
coal around 1.3 *10^3 J/kgK
5 * 1.3 *10^3 * 200 = 1,300,000
so a.
Sure, I can help you with these questions!
For the first question, we are being asked about the stage of internal combustion engine operation in which the piston rises and compresses the fuel in the combustion chamber. To determine the correct answer, we need to understand what happens during this stage.
During the compression stroke, the piston moves upward, compressing the fuel-air mixture in the combustion chamber. Both the intake and exhaust valves should be closed during this stage to ensure the proper compression of the mixture.
From the given options, the correct answer is:
c. Both the intake and exhaust valves are closed
Now, let's move on to the second question.
To calculate the amount of heat energy required to raise the temperature of a substance, we need to use the specific heat formula:
Q = mcΔT
Where:
Q is the heat energy (in joules)
m is the mass of the substance (in kilograms)
c is the specific heat capacity of the substance (in joules per kilogram per degree Celsius)
ΔT is the change in temperature (in degrees Celsius)
In this case, we are given:
m = 5 kilograms
c = specific heat capacity of coal (unknown)
ΔT = 220°C - 20°C = 200°C
To find the specific heat capacity of coal, we can use a reliable source such as a physics textbook or online reference. However, without that information, we cannot determine the exact answer.
Therefore, the correct answer is: None of the given options can be determined without knowing the specific heat capacity of coal.
I hope this helps you understand how to answer these questions in the future! If you have any more questions, feel free to ask.