Answer:
E. None of these
Explanation:
We know, By GAS laws,
PV = NRT, where p- pressure, v- volume, n- number of moles, R- gas constant ,and T- temperature
Now, In the question, the number of moles remains the same as the gas is the same. so n is constant so we can compare n before and after a temperature change.
= 
where P1= 1 atm, P2 = 10 atm, V1= 20 mL, T1= 10°C and T2= 100°C
We don't have to worry about the standard units as they are present equally on both the sides and get cut, same goes for R( gas constant)
So putting values, we get
Cutting, R on both sides and moving contents to the right so that only V2 is left on the left.
∴ V2 = 
∴ V2 = 20mL
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Answer:
6 different frequencies
Explanation:
From energy level 1 to 2 is one frequency, from energy level 1 to 3 is one frequency and From energy level 1 to 4 is one frequency. So, we have a total of 3 frequencies for transition from energy level 1.
From energy level 2 to 3 is one frequency and from energy level 2 to 4 is one frequency. So, we have a total of 2 frequencies for transition from energy level 2.
From energy level 3 to 4 is one frequency.
So we have a total of 3 + 2 + 1 different frequencies = 6 different frequencies.
Note that the reverse process for each step produces the same frequency as the step in consideration.
Answer: the pH of the solution is 4.52
Explanation:
Consider the weak acid as Ha, it is dissociated as expressed below
HA H⁺ + A⁻
the Henderson -Haselbach equation can be expressed as;
pH = pKa + log( [A⁻] / [HA])
the weak acid is dissociated into H⁺ and A⁻ ions in the solution.
now the conjugate base of the weak acid HA is
HA(aq) {weak acid} H⁺(aq) + A⁻(aq) {conjugate base}
so now we calculate the value of Kₐ as well as pH value by substituting the values of the concentrations into the equation;
pKₐ = -logKₐ
pKₐ = -log ( 7.4×10⁻⁵ )
pKₐ = 4.13
now thw pH is
pH = pKₐ + log( [A⁻] / [HA])
pH = 4.13 + log( [0.540] / [0.220])
pH = 4.13 + 0.3899
pH = 4.5199 = 4.52
Therefore the pH of the solution is 4.52
<em>Chemists use the mole unit to represent 6.022 × 10 23 things, whether the things are atoms of elements or molecules of compounds. This number, called Avogadro's number, is important because this number of atoms or molecules has the same mass in grams as one atom or molecule has in atomic mass units. </em>
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