Answer:
(C) arsenious acid, Ka = 6 x 10⁻¹⁰
Explanation:
A buffer is prepared by a weak acid and the conjugate base coming from its salt. Its function is to resist abrupt changes in pH when an acid or a base are added. The best working range of a buffer is in the range of pKa ± 1. Let's consider the 5 options and their pKa (pKa = -log Ka).
(A) phthalic acid, K1 = 1.3 x 10⁻³ (1st ionization) pKa = 2.9
(B) hydrogen phthalate, K2 = 3.9 x 10⁻⁵ pKa = 4.4
(C) arsenious acid, Ka = 6 x 10⁻¹⁰ pKa = 9
(D) formic acid, Ka = 1.8 x 10⁻⁵ pKa = 4.7
(E) phenol, Ka = 1.3 x 10⁻¹⁰ pKa = 9.8
The acid whose pKa is closer to the desired pH is arsenious acid. Its working range of pH is 8 - 10. In the second place, phenol could work as a buffer system since the working pH range is 8.8 - 10.8.
Answer:
liquid
Explanation:
In the given context, the sample as collected by Carmen is clear and the sample has a sour smell. It is also mentioned that the sample is thick sample and when the sample is poured on a surface it begins to flow.
Such a sample would be a liquid sample because anything that flows is a liquid. The liquid sample has a high viscosity since it is thick.
Answer:
1 fempto = 10⁻¹⁵
Explanation:
Data Given:
9.2 fempto second = 9.2 ×10 ⁻¹⁵ seconds
exponential equivalent of fempto = ?
Solution:
To find exponential equivalent of fempto
As we know
we look at the given data
That is fempto seconds = 9.2
when we write only seconds then we write 10⁻¹⁵ instead of fempto
that is
9.2 ×10 ⁻¹⁵ seconds
So the exponential equivalent of fempto = 10 ⁻¹⁵
That is -15 exponent to 10
So,
10 ⁻¹⁵ = 0.00000000000001
1 fempto = 10 ⁻¹⁵
Answer:
A.
Explanation:
Potential energy. Potential energy is energy that is stored.
Answer:
The mol fraction of cyclohexane in the liquid phase is 0.368
Explanation:
Step 1: Data given
Mass of cyclohexane = 25.0 grams
Mass of 2-methylpentane = 44.0 grams
Temperature = 35.0 °C
The pressure of cyclohexane = 150 torr
The pressure of 2-methylpentane = 313 torr
The pressure we only need for the mole fraction in gas phase.
Step 2: Calculate moles of cyclohexane
Moles cyclohexane = mass cyclohexane / molar mass
Moles cyclohexane = 25.0 g / 84 g/mol = 0.298 mol of cyclohexane
Step 3: Calculate moles of 2-methylpentane
Moles = 44.0 grams / 86 g/mol = 0.512 mol of 2-methylpentane
Step 4: Calculate mole fraction of cyclohexane in the liquid phase
Mole fraction of C6H12:
0.298 / (0.298 + 0.512) = 0.368
The mol fraction of cyclohexane in the liquid phase is 0.368
