Suppose that you have 135 mL of a buffer that is 0.360 M in both propanoic acid ( C 2 H 5 COOH ) and its conjugate base ( C 2 H 5 COO − ) . Calculate the maximum volume of 0.240 M HCl that can be added to the buffer before its buffering capacity is lost.

202.50 ml is the maximum volume of 0.240 M HCl that can be added to the buffer before its buffering capacity is lost.

Explanation:

Data given:

volume of buffer = 135 ml or 0.135 litres

molarity of the buffer = 0.360  M

volume of the acid = ?

molarity of the acid = 0.24 M

the number of moles of conjugate base is

M X V = number of moles

0.360 X 0.135

0.0486 moles of conjugate base

The maximum amount of acid added will equal the amount of conjugate base from the buffer.

So, the volume of acid will be calculated by using the formula:

Molarity =

 volume =

              = 0.2025 l

202.50 ml is the volume of acid added.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

gold is my favorite solid.