126.751 g/mol
Formula: FeCl2
They should report the density as 1.11 g/L
.
Density = mass/volume = 2.260g/2.04 mL
My calculator says the density <em>1.107 843 137 g/mL</em>
However, the answer can have <em>no more</em> significant figures than are in the number with the <em>fewest </em>significant figures.
The volume measurement has only three significant figures, so we must round off the density to three significant figures.
We drop all the digits after the zero.
The digit to be dropped is 7, so we <em>round up </em>the last significant figure of the answer.
1.10<u>7 843 137</u> → 1.11
Move and tilt<<<<<<<<<<<<<<<<
Answer:
Pyruvic acid: conjugate base
Lactic acid: conjugate base
Explanation:
The ratio of conjugate base to conjugate acid can be found using the Henderson-Hasselbalch equation when the pH and pKa are known.
pH = pKa + log([A⁻]/[HA])
The equation can be rearranged to solve for the ratio:
pH - pKa = log([A⁻]/[HA])
[A⁻]/[HA] = 10^(pH-pKa)
Now we can calculate the ratio for the pyruvic acid:
[A⁻]/[HA] = 10^(pH-pKa) = 10^(7.4 - 2.50) = 79433
[A⁻] = 79433[HA]
There is a much higher concentration of the conjugate base.
Similarly for lactic acid:
[A⁻]/[HA] = 10^(pH-pKa) = 10^(7.4 - 3.86) = 3467
[A⁻] = 3467[HA]
For lactic acid the conjugate base also dominates at pH 7.4
