The balanced chemical reaction is given above however I believe the coefficients are wrong. It should be:
4K + O2 = 2K2O
We use data from that reaction to obtain relationships between substances. We are given the amount of potassium that reacts. We proceed as follows:
1.52 mol K ( 2 mol K2O / 4 mol K ) = 0.76 mol of K2O is formed
The answer should be (D) endothermic reaction.
Reason : - Reactions in which energy is absorbed are called endothermic reactions. In your provided question, 150 kcal energy is being <u>absorbed</u>, and thus, we can say that it is an endothermic reaction.
Explanation:
workdone = force x distance
force = mass x acceleration
30 x 10 = 300N
300N x 1m
workdone= 300J
Answer : The maximum number of electrons released = 
Explanation : Given,
Frequency = 
Kinetic energy = 
Total energy = 
First we have to calculate the work function of the metal.
Formula used :

where,
K.E = kinetic energy
h = Planck's constant = 
= frequency
w = work function
Now put all the given values in this formula, we get the work function of the metal.

By rearranging the terms, we get

Therefore, the works function of the metal is, 
Now we have to calculate the maximum number of electrons released.
The maximum number of electrons released = 
The maximum number of electrons released = 
Therefore, the maximum number of electrons released is 
Answer:
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