Question

How many molecules are in 235.6mL of a 1.5M NaOH solution? ​

Answer 1

Molarity is defined as moles of solute, which in your case is sodium hydroxide, NaOH, divided by liters of solution.

molarity = moles of solute

------------------------

litres of solution

SImply put, a 1-M solution will have 1 mole of solute dissolved in 1 liter of solution.

Now, you know that your solution has a molarityof 0.150 M and a volume of 19.0 mL.

Since the volume is much smaller than 1 L, you can expect to have fewer moles of sodium hydroxide in this sample than you would have had in a full liter of solution.

Convert the volume of the sample from mililiters to liters by using the conversion factor.

1 L = 10^3 mL

to get

235.6ml × 1

------------------- = 235.6×10^-3

10^3ml

This means that the number of moles of solute you get in this sample will be equal to

c = n

-----

V

n= c×V

n= 1.5moles 235.6 ×10^-3 L

---------- ×

L

= 0.3534 moles NAOH