A teacher wants to perform demonstration that illustrates both chemical and physical changes. Which would be the best demonstrat
ion that she could use? A) bending a piece of aluminum B) breaking a matchstick C) dissolving sugar in water D) burning a candle
1 answer:
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Answer:
It will take 3.3 s for [NOCl] to decrease to 0.042 M.
Explanation:
Integrated rate law for this second order reaction-
where, [NOCl] is concentration of NOCl after "t" time, is initial concentration of NOCl and k is rate constant.
Here, = 0.076 M, k = 3.2
and [NOCl] = 0.042 M
So,
or, t = 3.3 s
So, it will take 3.3 s for [NOCl] to decrease to 0.042 M.
Answer:
The kinetic energy of the two stones is 320 J
Explanation:
Kinetic energy is the energy that a body possesses due to its movement. So it is the capacity or work that allows an object to go from being at rest, or still, to moving at a certain speed.
In other words, the kinetic energy of an object is that which is produced due to its motion and depends on its mass and velocity as follows:
where the kinetic energy Ec is measured in joules (J), the mass m is measured in kilograms (kg) and the velocity v in meters/second (m/s).
In this case you know that a 20 kg curling stone is sliding in a positive direction at 4 m/s. So:
- m= 20 kg
- v= 4 m/s
Replacing you have:
Ec₁= 160 J
A second curling stone slides at the same speed but in the opposite direction. So:
- m= 20 kg
- v= - 4 m/s
Replacing you have:
Ec₂= 160 J
The kinetic energy of the two stones is calculated as:
Ec= Ec₁ + Ec₂
Ec= 160 J + 160 J
Ec= 320 J
<u><em>The kinetic energy of the two stones is 320 J</em></u>