Answer:
a) The exit temperature is 430 K
b) The inlet and exit areas are 0.0096 m² and 0.051 m²
Explanation:
a) Given:
T₁ = 127°C = 400 K
At 400 K, h₁ = 400.98 kJ/kg (ideal gas properties table)
The energy equation is:
For a diffuser, w = Δp = 0
The diffuser is adiabatic, q = 0
Replacing:
Where
V₁ = 250 m/s
V₂ = 40 m/s
Replacing:
Using tables, at 431.43 kJ/kg the temperature is 430 K
b) The inlet area is:
The exit area is:
Answer:
C
Explanation:
Given that a liquid at rest in a fixed container exerts a force perpendicular to the wall of the container. Two students make claims about the microscopic cause of this force. Student A says that the force exerted by individual molecules as they bounce off the wall is always perpendicular to the wall. Student B says that the molecules may strike the wall at angles that are not perpendicular. Which student is correct and why?
The correct answer is option C
Student B . The molecules in a liquid are in random motion at the microscopic scale. For every atom that hits at an angle to one side of perpendicular, there is likely to be another atom hitting at the same speed at the same angle on the other side of perpendicular. On average the nonperpendicular components cancel
22. reduction
25. Le Chatelier's principle
Answer:
maximum power = 300 W
Explanation:
Ohm's law: Ohm's law state that the current flowing through a metallic conductor, is directly proportional to the potential difference applied across its end. mathematically it is expressed as,
V = IR............. Equation 1
Where V = potential difference, I = current, R = Resistance of the conductor.
If the power flowing through is gives as
W = 120I - 12I² ..................... Equation 2
To get the maximum power we differentiate of equation 2 and equate to zero
dW/dt = 0
120 - 24l = 0........................... equation 3
Making I the subject of the equation,
I = 120/24 = 5 A.
Suubstituting the value of I into Equation 2
W = 120 (5) - 12(5)²
W = 600 - 300
W = 300 W.
Therefore maximum power = 300 W
Answer:
15 kJ
Explanation:
We need to know the following;
what is activation energy?
- Activation energy is the minimum energy required by reactants for a chemical reaction to take place.
What are catalysts?
- Catalysts are molecules or substances that speed up the rate of a chemical reaction.
- In other words, catalysts increase the speed at which products are formed from reactants.
How do catalysts speed up reactions?
- Catalysts speed the rate of chemical reactions by lowering the activation energy of the reactants.
- When activation energy is lowered, reactants require less energy for the reaction to occur which easily achieved making the reaction proceed faster.
- Therefore, in presence of a catalyst, the new activation energy should be lower than the initial value of activation energy.
