Answer: 
Explanation:
Geometrical symmetry of the molecule and the polarity of the bonds determine the polarity of the molecule.
The molecule that has zero dipole moment that means it is a geometrically symmetric molecule and the molecule which has some net dipole moment means it is a geometrically asymmetric molecule.
As the molecule is symmetric, the dipole moment will be zero as dipole moments cancel each other and the molecule will be non-polar.
As the molecule is asymmetric, the dipole moment will not be zero and the molecule will be polar.
Example: 
Thus, we can say that
is a polar molecule.
Answer:
This question sadly does not make much sense, please rephrase it.
Hey there!
The correct answer to your question is option A.
Sugar dissolving in warm water is an example of a physical change.
This is because sugar dissolving in the water does not create a substance or material. All of the other options are examples of chemical changes, because they eventually become a substance/material.
Hope this helps you.
Have a great day!
Density = mass/volume
Since there was no condition of unit attached to the question...
Density = 100g/25.0ml
Density = 4g/mL.......
Moles of MgS2O3 = 247/136 = 1.81 moles. Molecular mass of MgS2O3 = 136