A. Adding iodine
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B. Electric current requires a specific path to follow.
A solute is a substance that dissolves into another substance , and forms a solution.
They can still be effected it large quantities of soap are added to water
because more soap eliminates the effect the minerals in hard water has on
its cleaning capacity.
Hard water contains minerals such as
They reduce the cleaning capacity of the soap. This is why soft water is
preferably used as it doesn't contain these minerals.
When more soap is added, the effect of the minerals reduces thereby
bringing about very little or no effect on the cleaning capacity of the soap.
Read more about Soap here brainly.com/question/1473301
Answer:
Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.
Explanation:
Percentage of element in compound :

(a) Urea, 
Molar mass of urea = 60 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 2

(b) Ammonium nitrate, 
Molar mass of ammonium nitrate = 80 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 2

(c) Nitric oxide, NO
Molar mass of nitric oxide = 30 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 1

(d) Ammonia, 
Molar mass of ammona = 17 g/mol
Atomic mass of nitrogen = 14 g/mol
Number of nitrogen atoms = 1
Ammonia is the richest source of nitrogen on a mass percentage basis because it has 82.35% of nitrogen by mass.