a. How many moles of NaOH are present in 89.6 mL of 0.714 M NaOH?
6.40E-2
b. How many moles of HCl are present in a 30.0 mL sample that is neutralized by the 89.6 mL of 0.714 M NaOH?
6.40E-2
c. What is the molar concentration of the HCl solution described in part b of this question?
2.13 M
To find the number of moles of a substance, you can use the equation:
moles = concentration x volume
a. In this case, you have the concentration of NaOH (0.714 M) and the volume (89.6 mL). The units of the concentration need to match the units of the volume. Since the volume is given in mL, you can directly use it in the equation. The calculation would be:
moles = 0.714 M x 89.6 mL
To get the answer in moles, you need to convert mL to L, so divide by 1000:
moles = 0.714 M x (89.6 mL / 1000 mL/L)
Simplifying the expression:
moles = 0.714 M x 0.0896 L
moles = 0.064 moles (rounded to two decimal places)
Therefore, the number of moles of NaOH present in 89.6 mL of 0.714 M NaOH is 0.064 moles.
b. Since the NaOH and HCl react in a 1:1 ratio, the moles of HCl will also be 0.064 moles. This is because the number of moles of the neutralizing agent (NaOH) is equal to the number of moles of the substance being neutralized (HCl).
c. To calculate the molar concentration of the HCl solution, you would use the same equation:
concentration = moles / volume
The volume of the HCl solution is given as 30.0 mL. The number of moles of HCl is 0.064 moles (as calculated in part b). Plugging these values into the equation:
concentration = 0.064 moles / 30.0 mL
Again, you need to convert mL to L by dividing by 1000:
concentration = 0.064 moles / (30.0 mL / 1000 mL/L)
Simplifying the expression:
concentration = 0.064 moles / 0.030 L
concentration = 2.13 M (rounded to two decimal places)
Therefore, the molar concentration of the HCl solution described in part b of this question is 2.13 M.