Respuesta :
Explanation
We are asked for the amount of NaOH used, that is, the grams of NaOH. We can initially find the volume of the NaOH solution that was used. To do this we subtract the initial volume of the solution minus the final volume, the result will be the volume used.
[tex]\begin{gathered} VolumeUsed=StartingVolume-FinalVolume \\ VolumeUsed=70mL-45mL=25mL \end{gathered}[/tex]Now, we will find the moles present in the solution used. For this, we will use the molarity of the solution. Molarity is defined as the number of moles per liter of solution, so we can isolate the number of moles from the equation.
[tex]Molarity=\frac{MolesSolute}{Lsolution}[/tex][tex]Molessolute=Molarity\times Lsolution[/tex]Molarity=1M=1mol/L
Lsolution=25mL=0.025L
[tex]MolesSolute=1\frac{mol}{L}\times0.025L=0.025mol[/tex]Now, we will find the amount in grams of NaOH used. We will multiply the moles by the molar mass of NaOH. The molar mass of NaOH is 39.997g/mol. So, the amount of NaOH will be:
[tex]gNaOH=givenmolNaOH\times\frac{MolarMass,gNaOH}{1molNaOH}[/tex][tex]gNaOH=0.025molNaOH\times\frac{39.997NaOH}{1molNaOH}=1.0gNaOH[/tex]Answer: So, the amount in grams of NaOH used is 1.0 g
