Select all of the statements that are true about a buffer solution. Select one or more: a. A buffer solution reacts with basic s
olutions. b. A buffer solution has a pH of 7. c. A buffer solution reacts with acidic solutions. d. A buffer solution always changes color when the pH changes. e. A buffer solution resists small changes in pH. Question 13 Not yet answered Marked out of 1.00 Not flaggedFlag question Question text At what point on the titration curve for a weak acid is the solution a buffer
1 answer:
Answer:
a. A buffer solution reacts with basic solutions.
c. A buffer solution reacts with acidic solutions.
e. A buffer solution resists small changes in pH
Explanation:
1. Buffer questions
a, c, and e are TRUE. A buffer resists a change in the pH when small amounts of a strong acid or base are added to it.
b is wrong. A buffer can have a pH of 7, but it can also have many other pH values.
d is wrong. Most buffers are colourless, and they resist a change in pH.
2. Titration curves
The solution is the best buffer at the mid-point of the titration curve.
In the figure below, the equivalence point is at 13 mL, so the mid-point is at 6.5 mL.
The solution is buffered at pH 3.2.
However, the solution is a buffer at any point in the range pH = 3.2 ± 1.
That would be in the range of 1 mL to 12 mL.
The buffering ability becomes worse the further you are from the mid-point of the titration.
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Answer:
Explanation:
<u>Convert Atoms to Moles</u>
The first step is to convert atoms to moles. 1 mole of every substance has the same number of particles: 6.022 ×10²³ or Avogadro's Number. The type of particle can be different, in this case it is atoms of silver. Let's create a ratio using this information.
We are trying to find the mass of 8.23 ×10²³ silver atoms, so we multiply by that number.
Flip the ratio so the atoms of silver cancel. The ratio is equivalent, but places the other value with units "atoms Ag" in the denominator.
Condense into one fraction.
<u>Convert Moles to Grams</u>
The next step is to convert the moles to grams. This uses the molar mass, which is equivalent to the atomic mass on the Periodic Table, but the units are grams per mole.
- Ag: 107.868 g/mol
Let's make another ratio using this information.
Multiply by the number of moles we calculated.
The moles of silver cancel out.
<u>Round</u>
The original measurement of atoms has 3 significant figures, so our answer must have the same. For the number we calculated, that is the ones place.
- 147.<u>4</u>184058
The 4 in the tenths place tells us to leave the 7 in the ones place.
8.23 ×10²³ silver atoms are equal to approximately <u>147 grams.</u>