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%
A. F = ma
B. F = md
C. F = m/a
D. F = m/d
b. Alkyne series
c. Saturated hydrocarbons
d. Unsaturated hydrocarbons
e. Aromatic hydrocarbons
(2) The nucleus is positive and the electron cloud is negative.
(3) The nucleus is negative and the electron cloud is positive.
(4) The nucleus is negative and the electron cloud is negative.
Atoms are made of nucleus and electrons. Nucleus have a positive charge due to the presence of protons and electrons are negative in charge . Thus option 2 is correct.
Atoms are the basic unit every substance. Atoms combines to form molecules and compounds. An atom is made of nucleus and surrounding electrons which are revolving through a circular path of fixed energy.
Nucleus is the core of the atom and the 90% of the weight of atom is centered in the nucleus and it contains positively charged protons and neutral particles neutrons.
The nuclear model of atom was first proposed by Rutherford. He found the positive cloud of the atom and and named as nucleus. He discovered the positively charged particles protons.
The net charge of an atom is zero because all the positive charges are neutralised by equal number of negatively charged particles electrons.
Therefore, the nucleus is positive and the electron cloud is negative and option 2 is correct.
To find more about atomic nucleus, refer the link below:
#SPJ2
a base
an acid
neutrality
Answer: C) Neutrality
Explanation:
Answer:
Neutrality
Explanation:
Answer:
same number of protons as electrons
Explanation:
The addition of a neutron can make an atom radioactive. When you change the number of protons in an atom, you will change the atom from one element to a different element. ... If you change the number of electrons in an atom, you will get an ion of the element.