You're performing a titration of some acetic acid. You have reason to doubt that the grocery store is selling you vinegar at the concentration listed on the label. The label says the contents are 2.00M acetic acid. You begin performing the titration on 5mL of the acetic acid sample with 0.11M NaOH. You perform the titration and find that your indicator (phenolphthalein) turns the slightest shade of pink and determine you've added 39.5mL of the 0.11M NaOH.
What is the concentration of the acetic acid purchased from the grocery? In your answer below, please only enter a numerical value. If you enter a unit, your answer will be counted wrong. It is understood that the unit is Molar (M).
1.78M
Hmm, it seems like the grocery store might just be bottling colorful water instead of vinegar! Let's do some calculations to find out the actual concentration of the acetic acid.
First, let's calculate the moles of NaOH used in the titration:
Moles of NaOH = Concentration of NaOH × Volume of NaOH used
= 0.11M × 39.5mL
= 4.345 moles
Since acetic acid and NaOH react in a 1:1 ratio, the moles of NaOH used is equal to the moles of acetic acid in the sample. Therefore:
Moles of acetic acid = Moles of NaOH
= 4.345 moles
Now, let's calculate the concentration of the acetic acid:
Concentration of acetic acid = Moles of acetic acid / Volume of acetic acid
= 4.345 moles / 5mL
= 0.869 M
So, it turns out that the concentration of the acetic acid purchased from the grocery store is approximately 0.869 M. But hey, at least it's not just colored water!
To find the concentration of the acetic acid purchased, we can use the formula:
M(acetic acid) * V(acetic acid) = M(NaOH) * V(NaOH)
Where:
M(acetic acid) = concentration of acetic acid purchased
V(acetic acid) = volume of acetic acid used in the titration (in liters)
M(NaOH) = concentration of NaOH used in the titration
V(NaOH) = volume of NaOH used in the titration (in liters)
Given:
V(acetic acid) = 5 mL = 5/1000 L = 0.005 L
M(NaOH) = 0.11 M
V(NaOH) = 39.5 mL = 39.5/1000 L = 0.0395 L
Plugging in the values into the formula:
M(acetic acid) * 0.005 L = 0.11 M * 0.0395 L
Simplifying the equation:
M(acetic acid) = (0.11 M * 0.0395 L) / 0.005 L
M(acetic acid) = 0.8645 M
Therefore, the concentration of the acetic acid purchased from the grocery is approximately 0.8645 M.
To determine the concentration of the acetic acid purchased from the grocery store, we can use the concept of stoichiometry in the titration reaction.
The balanced equation for the reaction between acetic acid (CH3COOH) and sodium hydroxide (NaOH) is as follows:
CH3COOH + NaOH -> CH3COONa + H2O
From the equation, we can see that the stoichiometric ratio between acetic acid and sodium hydroxide is 1:1. This means that 1 mole of acetic acid reacts with 1 mole of sodium hydroxide.
Given that the volume of acetic acid used in the titration is 5 mL, it can be converted to liters by dividing by 1000:
Volume of acetic acid = 5 mL = 0.005 L
The volume of sodium hydroxide used in the titration is 39.5 mL, which can also be converted to liters:
Volume of sodium hydroxide = 39.5 mL = 0.0395 L
Since the concentration of sodium hydroxide (NaOH) used is 0.11 M, we can calculate the moles of sodium hydroxide used in the titration:
Moles of NaOH = concentration × volume
= 0.11 M × 0.0395 L
= 0.004345 mol
Since the stoichiometric ratio is 1:1, the moles of acetic acid used in the titration are equal to 0.004345 mol.
Now we have all the information we need to calculate the concentration of the acetic acid.
Concentration of acetic acid = moles of acetic acid / volume of acetic acid
= 0.004345 mol / 0.005 L
= 0.869 M
Therefore, the concentration of the acetic acid purchased from the grocery store is approximately 0.869 M.