7.20 it the energy because
10\7.26 is 7.20
- 70
26
-20
6
Prarie Grass Protects soil ( And this is just what I think, so I am sorry if I am wrong)
But I think that the grass is there so that the dirt doesn't fly away.
Answer : The molecular weight of a substance is 157.3 g/mol
Explanation :
As we are given that 7 % by weight that means 7 grams of solute present in 100 grams of solution.
Mass of solute = 7 g
Mass of solution = 100 g
Mass of solvent = 100 - 7 = 93 g
Formula used :

where,
= change in freezing point
= temperature of pure water = 
= temperature of solution = 
= freezing point constant of water = 
m = molality
Now put all the given values in this formula, we get


Therefore, the molecular weight of a substance is 157.3 g/mol