Answer:
69.3%
Explanation:
The question should read as follows:
A weak acid, HA, has a pKa of 4.357. If a solution of this acid has a pH of 4.005, what percentage of the acid is not ionized? Assume all H⁺ in the solution came from the ionization of HA.
The Henderson-Hasselbalch equation relates the pKa and pH of a solution to the ratio of ionized (A⁻) and unionized (HA) forms of a weak acid:
pH = pKa + log ([A⁻]/[HA])
Substituting and solving for [A⁻]/[HA]:
4.005 = 4.3574 = log([A⁻]/[HA])
-0.3524 = log([A⁻]/[HA])
[A⁻]/[HA] = 0.444/1
The percentage of acid that is not ionized (i.e. the percentage of acid in the HA form) is calculated:
[HA]/([A⁻] + [HA]) x 100% = 1/(1+0.444) x 100% = 69.3%
The volume of the liquid = 8.7 ml
<h3>Further explanation</h3>
Graduated cylinder is a laboratory tool used to measure the volume of liquid
Also called a measuring cylinder
Each line (marked line) on this cylinder shows a scale that shows the total volume of water.
The reading is based on a curve of the fluid formed called the meniscus. Read the measurement of the amount of fluid at the bottom of the meniscus (the position of our eyes is parallel to the level of the meniscus and the cylinder is located in a flat (not tilted) place
If we look at the picture (attached), the meniscus is located between the scale / line 8.6 and 8.8(interval 0.2 ml), so the volume of the liquid shows the number 8.7 ml
Answer:
CHCI₃
Explanation:
Chloroform, IUPAC name, trichloromethane, is organic compound with the molecular formula CHCl₃. It is colorless and sweet-smelling liquid having high density which is produced on a large scale precursor of PTFE , and for various refrigerants .
Chloroform , is a powerful euphoriant , anxiolytic , anesthetic and sedative when inhaled or ingested .
Answer:
Explanation:
q= mc theta
where,
Q = heat gained
m = mass of the substance = 670g
c = heat capacity of water= 4.1 J/g°C
theta =Change in temperature=(
66-25.7)
Now put all the given values in the above formula, we get the amount of heat needed.
q= mctheta
q=670*4.1*(66-25.7)
=670*4.1*40.3
=110704.1
