Answer:
ΔH = 180.6 kJ
Explanation:
Given that:
N2 (g) + 2O2(g) = 2NO2 (g) ΔH = 66.4 kJ
<u>2NO (g) + O2 (g) = 2NO2 (g) ΔH = -114.2 kJ </u>
N2 (g) + O2 (g) = 2NO (g) ΔH = ????
The subtraction of both equations would yield the unknown ΔH , therefore:
ΔH = 66.4 - ( - 114.2 kJ)
ΔH = 180.6 kJ
I think it’s the third option
Answer: The number 4 indicates 4 electrons.
Explanation: We are given an electronic configuration, which is:

Here,
- The letters denote the sub-shells of an element.
- The numbers written before the letters which are 1, 2 and 2 represents the Principle Quantum Number and these represents the energy level of the sub-shells.
- The number which are written in the superscripts which are 2, 2 and 4 denotes the electrons which are present in the sub-shell.
Hence, 4 indicates 4 electrons present in 2p sub-shell.
B I think lol when something changes the state of matter
Because lager objects have much more room for mass the smaller objects. take the earth as an example the earth is very big and has alot of mass in it which makes gravity that pulls us down when we jump up.