Answer:
A) 1059 J/mol
B) 17,920 J/mol
Explanation:
Given that:
Cp = 29.42 - (2.170*10^-3 ) T + (0.0582*10^-5 ) T2 + (1.305*10^-8 ) T3 – (0.823*10^-11) T4
R (constant) = 8.314
We know that:
We can determine 
from above if we make the subject of the formula as:
A).
The formula for calculating change in internal energy is given as:
If we integrate above data into the equation; it implies that:
Hence, the internal energy that must be added to nitrogen in order to increase its temperature from 450 to 500 K = 1059 J/mol.
B).
If we repeat part A for an initial temperature of 273 K and final temperature of 1073 K.
then T = 273 K & T2 = 1073 K
∴
40×19.32/100=7.7=8×2=16Ca
35.5×34.30/100=12.1=12×2=24Cl
16×46.38/100=7.4=7×2=14O
Answer: The reactivity of group 7 decreases as we move down the group because:
Explanation:
The elements of group 7 that is fluorine to iodine. The halogens are non metals and they react with metals to gain electrons. The metals loose electrons and the non metal gains it.
As we move down the group the atomic radius gets bigger( more electron and more proton) and as a result the outer shells move further away from the nucleus.
There is more distance between the negatively charged electrons and positively charged nucleus.
Therefore the force of attraction between the shells and nucleus is lesser or weaker.
This makes attracting an extra electron from metals very difficult which results in weaker reaction.
Consequently, the reactivity decreases as we move down the group 7
The answer is 1.5e+6. Hope this helped!
