Answer:
Explanation:
Depression in freezing point is given by:

= Depression in freezing point
i= vant hoff factor = 1 (for non electrolyte like urea)
= freezing point constant = 
m= molality

Weight of solvent (X)= 950 g = 0.95 kg
Molar mass of non electrolyte (urea) = 60.06 g/mol
Mass of non electrolyte (urea) added = ?


Thus
urea was dissolved.
2mm=2,000,000 nm
2,000,000/25=80,000
The answer is 80,000 polio viruses
<span>a. Tall prarie grass burns after being struck by lightning.</span>
Answer: Option (C) is the correct answer.
Explanation:
An ion is defined as a specie which is formed when a neutral atoms tends to gain or lose an electron.
When a neutral atom gain an electron then it forms a negative ion whereas when a neutral atom tends to lose an electron then it forms a positive ion.
For example, a neutral fluorine atom on gaining an electron will form
ion. And, a sodium atom on losing an electron forms
ion.
When a group of atoms form ions then it tends to form polyatomic ions.
Thus, we can conclude that group of atoms that gains or loses electrons is called a polyatomic ion.
<span>H2. Since the difference in electronegativity between two identical atoms is 0, the resulting molecule is non-polar.</span>