What are the given choices?
The amount of Li present to start the reaction is 55.18g
<u>Explanation:</u>
2Li + Br₂ → 2LiBr
Molecular weight of Br₂ = 159.808 g/mol
Mass of Br₂ present = 225 g
Moles of Br₂ present during the reaction = 225 / 159.808
m = 1.4
Molecular weight of LiBr = 86.845 g/mol
Mass of LiBr formed = 690 g
moles of LiBr produced = 690 / 86.845
m(LiBr) = 7.95
According to the balanced equation, 2 molecules of Li reacts to for 2 molecule of LiBr
So, 7.95 moles of LiBr would require 7.95 moles of Li
The molecular weight of Li is 6.941 g/mol
Thus, the amount of lithium present to start the reaction is
Therefore, the amount of Li present to start the reaction is 55.18g
Answer:
Consider the velocity-time graph attached below.
The velocity-time graph represents the acceleration of a body under a force.
We can see that is the graph that if a child release the ball above the ground at A, it hits the ground at B. Bounces back with a reaches the top again at C, and hits the ground again at D.
The slope of velocity time graph represents acceleration. From A to B, velocity in increasing constantly with respect to time, which means constant acceleration from A to B. AS velocity increase, momentum of the ball also increases, which results in the increase of Kinetic energy.
At B, the ball hits the ground, the velocity decreases, momentum decrease s, because kinetic energy is transferred from the ball to the ground, due to which the ball would not attain the same height after the bounce.
Then the velocity remains negative at C, which means that now the ball is moving in opposite direction till C. It reaches its new at height at C, which is not the same as that of A because of lost in Kinetic Energy, and fall again.
Answer:
Explanation:
All the energy in oil, gas, and coal originally came from the sun, captured through photosynthesis.for example when we burn wood to release energy that trees capture from the sun, we burn fossil fuels to release the energy that ancient plants captured from the sun. We can think of this energy as having been deposited in a natural solar power bank over millions of years.
So, in one sense, gasoline-burning cars, coal-burning power plants, and homes heated by natural gas are all solar powered!
Answer:
The average power is calculated as 735.0 W
Solution:
As per the question:
Total mass, M = 1200 kg
Counter mass of the elevator, m = 950
Distance traveled by the elevator, d = 54 m
Time taken, t = 3 min = 180 s
Now,
To calculate the average power:
First, we find the force needed for lifting the weight:
Force, F = (M - m)g =
Now, the work done by this force:
W = Fd =
Average power is given as: