The ph of the best buffer is 4.74
The given acetic acid is a weak acid
The equation of the pH of the buffer
pH = pKa + log ( conjugate base / weak acid ).
For best buffer the concentration of the weak acid and its conjugate base is equal.
pH = pKa + log 1
pH = pKa + 0
pH = pKa
given Ka = 1.8 × 10⁻⁵
pKa = - log ka
pH = -log ( 1.8 × 10⁻⁵ )
pH = 4. 74
Hence the pH of the best buffer is 4.74
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The answer is (4) Ag(s)
Solid Silver has a Face Centered Cubic crystal structure.
The remaining choices are gases (H2 & Ar) and liquid (Br). Liquids and gases do not form crystal structures as their atoms are loose.
The electrons closer to the nucleus would have more energy than the electrons farther away from the nucleus.
Answer:
See below :)
Explanation:
There is an evident reason why some of the solutions Carson's has listed and observed, does conduct electricity and some that do.
A flow of electrical charge is called an electric current. Ions are atoms, or sets of atoms, that contain an electrical charge. There are two types of ions, cation or a positively charged ion containing a deficiency of electrons, and anion or a negatively charged ion which contains a surplus of electrons. When a solution conducts electricity the charge is carried within by ions that move through the solution. The larger the number of ions in the solution, the better the conductivity of the solution is. Pure water does not conduct very well because it contains very few ions, but when table salt (NaCl) is dissolved in the water, this solution does conduct well because the solution contains a more abundance of ions. The majority of the ions come from the table salt, chemically names sodium chloride. Because Sodium contains its sodium ions, and these are positive charge and chloride ions which is a negative charge, it is called an ionic substance. Not every substance is made up of ions, one such example is sugar (C12H22O11). Sugar is made up of uncharged particles also called molecules. Although sugar is a substance its molecules do not hold a charge, thus when sugar is dissolved in water, the solution does not conduct electricity, due to the lack of ions in the solution.
Therefore, depending on the ions that make up the compound, the substance would or would not conduct electricity.
For this problem we can use half-life formula and radioactive decay formula.
Half-life formula,
t1/2 = ln 2 / λ
where, t1/2 is half-life and λ is radioactive decay constant.
t1/2 = 8.04 days
Hence,
8.04 days = ln 2 / λ
λ = ln 2 / 8.04 days
Radioactive decay law,
Nt = No e∧(-λt)
where, Nt is amount of compound at t time, No is amount of compound at t = 0 time, t is time taken to decay and λ is radioactive decay constant.
Nt = ?
No = 1.53 mg
λ = ln 2 / 8.04 days = 0.693 / 8.04 days
t = 13.0 days
By substituting,
Nt = 1.53 mg e∧((-0.693/8.04 days) x 13.0 days))
Nt = 0.4989 mg = 0.0.499 mg
Hence, mass of remaining sample after 13.0 days = 0.499 mg
The answer is "e"
