Answer:
w = -531 kJ
1. Work was done by the system.
Explanation:
Step 1: Given data
- Heat gained by the system (q): 687 kJ (By convention, when the system absorbs heat, q > 0).
- Change in the internal energy of the system (ΔU°): 156 kJ
Step 2: Calculate the work done (w)
We will use the following expression.
ΔU° = q + w
w = ΔU° - q
w = 156 kJ - 687 kJ
w = -531 kJ
By convention, when w < 0, work is done by the system on the surroundings.
The electronegativity of nitrogen (N) is 3.0, while the electronegativity of hydrogen (H) is 2.1. As it can be seen that nitrogen (N) is more electronegative than that of hydrogen (H),
So electron pairs are attracted towards nitrogen and thus it carries a partial negative charge and hydrogen carries a partial positive charge. The image of electron distribution is attached as follows.
Thus NH₃ is a polar molecule .
Answer:
The attractive force between them decreases
Explanation:
This is because they become localised.
Answer: The complete reaction is as follows.

Explanation:
When nucleus of two or more atoms are bombarded together then it leads to the formation of new particles with new identity. This type of reaction are called nuclear reaction.
For example, 
Here, nitrogen atom when bombarded with a neutron then it is forming hydrogen and a carbon atom.
As total atomic mass on reactant side is (14 + 1) = 15
So, the atomic mass of carbon formed on product side is (15 - 1) = 14.
The number of protons holded by this carbon atom is (7 - 1) = 6.
Therefore, we can conclude that the complete reaction is as follows.

Answer:
Volume occupied by oxygen gas at 15 degree centigrade is equal to
centimeter cube
Explanation:
Assuming Pressure is constant.

where T1 and T2 are temperature in Kelvin
Substituting the give values we get-


Volume occupied by oxygen gas at 15 degree centigrade is equal to
centimeter cube