Answer:

Explanation:
Given that,
The dimension of a square chunk of plastic is 5 cm × 5 cm × 5 cm
Mass, m = 200 g
We need to find its density
Density = mass/volume
It will form a cube. It volume = side³
So,

Hence density is 
The hardest to compress here would be the brick
5 times dilution
0.780M x 1/5 = 0.156M
Hope this help.
Answer:
on N overlaps with 1s on H.
Explanation:
Hybridization of central atom generally can be found by finding the hybridization number.Hybridization number is the sum of number of lone pairs and number of sigma bonds.
If hybridization number is 2 then the central atom is sp hybridized.
If it is 3 it is
hybridized.
If it is 4 it is
hybridized and so on.
Here in
molecule there are 3 sigma bonds and one lone pair(see the figure attached).
Hence hybridization number is 4 and hence it is s
hybridized.
And in case of hydrogen atom the only electron of it resides in the 1s orbital.
Therefore
on N overlaps with 1s on H.