What mass of #NaOH# is contained in 250.0 mL of a 0.400 M sodium hydroxide solution?

2 Answers
May 23, 2016

Answer:

#"Approx. 4 g of NaOH."#

Explanation:

#"Concentration"# #=# #"Moles"/"Volume of solution"#

#"Number of moles"# #=# #"Volume"xx"concentration "=#

#0.250*Lxx0.400*mol*L^-1#

#=# #0.100*mol#

#"Mass of sodium hydroxide"# #=# #0.100*molxx40.0*g*mol^-1#

#=??*g#

May 23, 2016

Answer:

3.998 grams NaOH

Explanation:

The Molarity of a solution is determined by the comparison of the moles of the solute compared to the volume of the solution in liters.

The equation of the formula is #M = (mol)/L#

In order to find the mass we first need to solve for the moles.

#mol = M/L#

M = 0.400
moles = ?
L = 250.0 mL or 0.25 L

#0.400 M (0.25 L) = (? mol)#

# 0.100 mol of NaOH#

Now we can calculate the grams be converting moles to grams.

#Na = 22.98 g#
#O = 15.99 g#
#H = 1.01 g#

#NaOH = 39.98 g#

#0.100 cancel(mol NaOH) x (39.98 g NaOH)/( 1 cancel(molNaOH)#

3.998 grams NaOH