This is an example of displacement reaction
<u>Explanation:</u>
- The chemical reaction in which the one element replaces the other element in a compound is called a displacement reaction. This reaction is also called a replacement reaction.
AB + C -----> AC +B
2ZnS + 3O2 -----> 2ZnO + 2SO2
- This happens when A is more reactive than B and gives a stable product. Here the zinc sulfide compound reacts with the oxygen element to the stable product of zinc oxide and sulfur dioxide.
- In short, the more reactive element displaces the less reactive element is called a displacement reaction.
DR is the correct answer
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Acid + alkali ------> salt + water
2KOH + H2SO4 ------> K2SO4 + 2H2O
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<u>Answer:</u> The internal energy change for the reaction is -2850 J
<u>Explanation:</u>
- <u>Sign convention of heat:</u>
When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.
- <u>Sign convention of work:</u>
Work done for expansion process is taken as negative and work done for compression is taken as positive.
According to the First law of thermodynamics,

where,
= internal energy
q = heat absorbed or released = -2290 J
w = work done = -560 J
Putting values in above equation, we get:

Hence, the internal energy change for the reaction is -2850 J
Electromagnetic wave travels faster through air than metal.
Option A
<u>Explanation:</u>
There are different kinds of wave energy. The most significant are electromagnetic and mechanical waves. The mechanical waves propagate through the medium by transfer of energy by vibrating of particles in medium.
So, the more number of particles present in the medium, the more fast the mechanical wave can propagate. So the mechanical waves travel faster in metals consisting of more number of free charge carriers. But electromagnetic waves does not need any of the medium to propagate. So it can travel faster in air than in metals.