How many moles of hydroxide ion are there in a 250 mL sample of 5.00 M solution of sodium hydroxide?

Answer 1

n=c/v

n=3M/.25L

n=12 mol

m=Mxn

m=58.443 g/mol x 12 mol

m=701.3 g

n= mol

c=concentration

v=volume

m=mass

M= molar mass

Tylerops:

I don't agree with this answer. Molarity is defined as Moles/Liters. In other words Molarity is the concentration of a solution. In the above n= Concentration / Liters. That is equal to saying Moles=(Moles/liters)/ Liters. In the above question the concentration is (3 moles/ liter), or 3M.

Plus, how can it be possible to have 12 moles in 250ml when you only have 3 moles in each liter of the original solution?

Correct ANSWER:

3.00 M, or 3 moles per (L) "liter" calls for having 3 moles per liter of the solution. The question asks how many moles must be in 250ml of a solution that has 3 moles per Liter.

You must ask yourself what percent of 1 Liter is 250mls? Since there are a thousand ml in one liter, (1000ml=1L), then 250ml is exactly 25% of a Liter, or .25L.

So, 250ml can only hold 25% of the 3.00 Molarity. Meaning that you multiply 3 x .25 and get .75 moles. 58.443g/molNaCl x .75 moles = FINAL ANSWER 43.83225g NaCl, Sig Fig, 43.83gNaCl

Answer 2

Molarity = moles of solute/Liters of solution. ( 250 milliliters = 0.250 Liters )

1.5 M NaOH = moles NaOH/0.250 Liters

= 0.375 moles NaOH, or, with sigi figis right

0.38 moles NaOH

Answer 3

250 mL is 0.250 liter. By definition, each liter of a 5.00 M solution contains 5 moles of sodium hydroxide, and each mole of sodium hydroxide contains one mole each of sodium and of hydroxide ions. Therefore, the specified volume of the specified solution contains 0.250(5.00) or 1.25 moles of hydroxide ions, to the justified number of significant digits.

Answer 4

This molarity is 13 M; but this solution doesn't exist.

Answer 5

(3.25m)(.25l)=13.0m

Answer 6

0.25 moles

Answer 7

130mi

Answer 8

0.25 moles