Explanation:
The given data for case (1) is as follows.
h = 20 cm = 0.2 m
Assuming that a rectangular slab is placed above the pipe and we will calculate the heat transfer as follows.
Q = 
where, A = area
L = length
k = thermal conductivity = 0.8 W/m
= change in temperature.
Therefore, putting the given values into the above formula as follows.
Q =
= 
= 168 W
For case (2), h = 180 cm = 1.8 m
Therefore, heat lost will be calculated as follows.
Q =
= 
= 18.67 W
Thus, we can conclude that 18.67 W heat lost if the pipe was buried at a depth of 180 cm.
The complete question is shown in the image attached to this answer.
Answer:
C
Explanation:
Let us quickly remember that the EMF of a cell under non standard conditions in given by the Nernst equation.
This equation states that;
E = E°cell - 0.592/n log Q
Where
E = EMF under non standard conditions
E°cell= standard EMF of the cell
n = number of electrons transferred
Q = reaction quotient
If the reaction quotient is greater than 1 then cell potential is less than the standard cell potential.
The cell that generates the lowest cell potential is the cell depicted in option C because Q has the greatest positive value(Q<1).
Answer:
ΔS=0.148 KJ/K
Explanation:
Given that
Q = 100 KJ
T₁=200°C
T₁=200+273 = 437 K
T₂=5°C
T₂=5 + 273 = 278 K
Reservoir 1 is rejecting heat that is why it taken as negative while the reservoir 2 is gaining the heat that is why it is taken as positive.
So the total change in entropy given as
ΔS= - Q/T₁ + Q/T₂
ΔS= - 100/473 + 100/278 KJ/K
ΔS=0.148 KJ/K
Complete question is;
When the concentrations of reactant molecules are increased, the rate of reaction increases. The best explanation for this phenomenon is that as the reactant concentration increases,
A)the average kinetic energy of molecules increases.
B)the frequency of molecular collisions increases.
C)the rate constant increases.
D)the activation energy increases.
E)the order of reaction increases.
Answer:
B) The frequency of molecular collisions increases.
Explanation:
When we increase number of reactant molecules, the effective collision between the reactant molecules will form a product which also increases. As a result, the overall rate of the reaction will also increase which means the frequency of the molecular collision will also increase as well.
Thus, the correct answer is Option B
The answer is C by vibrating the molecules in the matter
