QUESTION 4
Data Set 3:
47.65 mL of a standard 0.1000 mol L–1 HCl solution is used to titrate a 0.3827 g sample containing NaOH and other impurities. None of the impurities reacted with the HCl.
What is the mass of NaOH in the sample?
a.
0.1737 g
b.
0.2103 g
c.
0.1906 g
d.
0.1542 g
1737 g
it was 0.1906 i figured it out
HOW did you figure this out?
To find the mass of NaOH in the sample, we need to use the concept of stoichiometry and the titration reaction between HCl and NaOH. From the given information, we know the volume of HCl used in the titration (47.65 mL), and the concentration of HCl (0.1000 mol L–1).
We need to calculate the number of moles of HCl used in the titration using the concentration and volume of HCl:
moles HCl = concentration x volume
= 0.1000 mol L–1 x 0.04765 L
= 0.004765 mol
According to the balanced chemical equation for the reaction between HCl and NaOH:
HCl + NaOH → NaCl + H2O
The ratio of HCl to NaOH is 1:1. This means that the number of moles of NaOH is equal to the number of moles of HCl used in the titration. Therefore, the number of moles of NaOH in the sample is also 0.004765 mol.
To calculate the mass of NaOH, we can use the molar mass of NaOH:
molar mass of NaOH = 22.99 g/mol + 16.00 g/mol + 1.01 g/mol
= 39.00 g/mol
mass of NaOH = number of moles x molar mass
= 0.004765 mol x 39.00 g/mol
= 0.18554 g
Therefore, the mass of NaOH in the sample is approximately 0.1855 g. None of the options provided match this value exactly, so the closest option is 0.1906 g (c).