how many milliliters of the acetic acid (density:1.049g/ml)must be adding to 465m l of a 0 .0941m sodium hydroxide to obtain a buffer?
The amount is variable; it depends upon the pH you want the buffer to have.
To determine how many milliliters of acetic acid should be added to the sodium hydroxide to obtain a buffer, we need to set up an equation based on the equation for calculating the concentration of a buffer solution.
A buffer solution is a solution that resists changes in pH when small amounts of acid or base are added to it. It is made up of a weak acid and its conjugate base (or a weak base and its conjugate acid).
In this case, acetic acid (CH3COOH) is the weak acid, and sodium hydroxide (NaOH) is the strong base. The reaction between them can be represented as follows:
CH3COOH + NaOH → CH3COONa + H2O
First, let's determine the number of moles of sodium hydroxide in the given 465 ml of the 0.0941 M solution. The concentration of the solution tells us that there are 0.0941 moles of sodium hydroxide per liter (1000 ml) of solution. Therefore, the number of moles of sodium hydroxide in 465 ml can be calculated as follows:
moles of NaOH = (0.0941 M) * (0.465 L) = 0.0437 moles
Since acetic acid and sodium hydroxide react in a 1:1 stoichiometric ratio, we need an equal number of moles of acetic acid to neutralize the sodium hydroxide. Therefore, we will need 0.0437 moles of acetic acid.
Next, we can use the density of acetic acid to convert the number of moles into milliliters. The density of acetic acid is given as 1.049 g/ml.
First, convert the number of moles to grams:
grams of acetic acid = (moles of acetic acid) * (molar mass of acetic acid)
The molar mass of acetic acid (CH3COOH) is calculated as:
(12.01 g/mol * 2) + (1.01 g/mol * 4) + (16.00 g/mol) + (1.008 g/mol) = 60.052 g/mol
Using this molar mass, we can calculate the grams of acetic acid:
grams of acetic acid = (0.0437 mol) * (60.052 g/mol) = 2.622 g
Finally, we can convert the grams to milliliters using the density:
milliliters of acetic acid = (grams of acetic acid) / (density of acetic acid)
milliliters of acetic acid = (2.622 g) / (1.049 g/ml) = 2.498 ml (rounded to three decimal places)
Therefore, approximately 2.498 milliliters of acetic acid should be added to the 465 ml of 0.0941 M sodium hydroxide to obtain a buffer solution.