Solution:
Benzoic acid is C6H5COOH
In finding pH
C6H5COOH(aq) <=> C6H5COO^- + H^+ pKa = 4.19, pKa = -logKa so Ka = 10^(-4.19)
Ka = 6.45 x 10^-6
[C6H5COO^-] = x = [H^+]; [C6H5COOH] = 0.5 - x (we are able to make an estimate of [C6H5COOH] = 0.5.
Ka = [H^+][C6H5COO^-]/[C6H5COOH] = x^2/(0.5 - x) = 6.45 x 10^-6
Now,
According to the quadratic equation. x^2 = 3.23 x 10^-5 - 6.45 x 10^-6x
x^2 + (6.45 x 10^-6)x - 3.23 x 10^-5 = 0
enter a = 1, b = 0.00000645, c = 0.0000323
x = 5.68 x 10^-3 = 0.00568 M expression is [C6H5COOH] = 0.5 M is the correct answer.
[H^+] = 0.00568 M, so pH = -log(0.00568 M ) = 2.25
This is the required solution.
Answer:
I believe your answer is B) make a prediction
Explanation:
Answer:
D.) They often form hydroxide ions.
Explanation:
They generate hydroxide ions in water. they are soapy to touch and bitter in taste. they conduct electricity.
(all bases have hydroxide ions)
Answer: 27 neutrons
Explanation:
Recall that the number of protons in the nucleus of an atom = Atomic number.
Hence, Calcium with mass number 47 and atomic number 20 will have 20 protons
Therefore, since Mass number = number of protons + neutrons
47 = 20 + neutrons
Neutrons = 47 - 20 = 27
Thus, there are 27 neutrons in radioactive calcium nucleus.
Answer:
Option A an E.
Explanation:
Energy can be described as the capability to do work. It is what has to be transferred to an object in order to get this object to do work. Energy can be in various forms such as heat energy, kinetic, potential, electrical, chemical, nuclear etc.
It takes energy to do quite a number of things, from cooking food to driving and also in engaging in exercises.
