Molality is a measure of concentration that relates the moles of solute to the kilograms of solvent, it is described by the following equation:

We are given the molality(2.50m) and kilograms of solvent(0.500kg), so we solve for moles of solute from the equation:


To make a 2.50molal NaOH solution would be needed 1.25moles of solute
Answer: 1.25 moles
Answer: The addition of salt in ice particles causes a decrease on its freezing point.
Explanation: salt definitely lowers the freezing point of ice particles.
Answer :
(a) 0.0152
(b) 0.0000000778
(c) 0.000001
(d) 1600.1
Explanation :
Scientific notation : It is the representation of expressing the numbers that are too big or too small and are represented in the decimal form with one digit before the decimal point times 10 raise to the power.
For example :
5000 is written as 
889.9 is written as 
In this examples, 5000 and 889.9 are written in the standard notation and
and
are written in the scientific notation.
(a) 
The standard notation is, 0.0152
(b) 
The standard notation is, 0.0000000778
(c) 
The standard notation is, 0.000001
(d) 
The standard notation is, 1600.1
The twin primes between 1 and 100 are; (3, 5), (5, 7), (11, 13), (17, 19), (29, 31), (41, 43), (59, 61), (71, 73). Hope this helped<3