The mass of ammonium chloride that must be added is : ( A ) 4.7 g
<u>Given data :</u>
Volume of water ( V ) = 250 mL = 0.25 L
pH of solution = 4.85
Kb = 1.8 * 10⁻⁵
Kw = 10⁻¹⁴
Given that the dissolution of NH₄Cl gives NH₄⁺⁺ and Cl⁻ ions the equation is written as :
NH₄CI + H₂O ⇄ NH₃ + H₃O⁺
where conc of H₃O⁺
[ H₃O⁺ ] = 
and Ka = Kw / Kb
∴ Ka = 5.56 * 10⁻¹⁰
Next step : Determine the concentration of H₃O⁺ in the solution
pH = - log [ H₃O⁺ ] = 4.85
∴ [ H₃O⁺ ] in the solution = 1.14125 * 10⁻⁵
Next step : Determine the concentration of NH₄CI in the solution
C = [ H₃O⁺ ]² / Ka
= ( 1.14125 * 10⁻⁵ )² / 5.56 * 10⁻¹⁰
= 0.359 mol / L
Determine the number of moles of NH₄CI in the solution
n = C . V
= 0.359 mol / L * 0.25 L = 0.08979 mole
Final step : determine the mass of ammonium chloride that must be added to 250 mL
mass = n * molar mass
= 0.08979 * 53.5 g/mol
= 4.80 g ≈ 4.7 grams
Therefore we can conclude that the mass of ammonium chloride that must be added is 4.7 g
Learn more about ammonium chloride : brainly.com/question/13050932
Answer:
"mole"
Explanation:
That is the definition of mole. Mole is a unit for the measurement of how much there is of something. In other words, in SI, 1 mol of a substance contains the same number of molecules/atoms as in 12 grams of carbon 12.
(Approximately 6.28 × 10^23 --> Avogadro's constant)
For further explanation, check out Wikipedia's article here:
https://en.m.wikipedia.org/wiki/Mole_(unit)
0.34 moles of gas would be contained in a 11.2 L container that is at a pressure of 0.75 atm and 300 K.
<h3>HOW TO CALCULATE NUMBER OF MOLES?</h3>
The number of moles of a substance can be calculated using the following expression:
PV = nRT
Where;
- p = pressure (atm)
- v = volume (L)
- n = number of moles
- R = gas law constant
- T = temperature
0.75 × 11.2 = n × 0.0821 × 300
8.4 = 24.63n
n = 8.4 ÷ 24.63
n = 0.34 moles
Therefore, 0.34 moles of gas would be contained in a 11.2 L container that is at a pressure of 0.75 atm and 300 K.
Learn more about number of moles at: brainly.com/question/1190311
Answer is: <span>the empirical formula of the hydrocarbon is CH</span>₂.<span>
Chemical reaction: C</span>ₓHₐ + O₂ → xC + a/2H₂O.<span>
m(CO</span>₂) = 33.01 g.
n(CO₂) = m(CO₂) ÷ M(CO₂).
n(CO₂) = 33.01 g ÷ 44.01 g/mol.
n(CO₂) = n(C) = 0.75 mol.
m(H₂O) = 13.52 g.
n(H₂O) = 13.52 g ÷ 18 g/mol.
n(H₂O) = 0.75 mol.
n(H) = 2 · n(H₂O) = 1.5 mol.
n(C) : n(H) = 0.75 mol : 1.5 mol /0.75 mol.
n(C) : n(H) = 1 : 2.
Answer:
Nuclear energy comes from splitting atoms in a reactor to heat water into steam, turn a turbine and generate electricity.
Explanation:
Ninety-five nuclear reactors in 29 states generate nearly 20 percent of the nation's electricity, all without carbon emissions because reactors use uranium, not fossil fuels.
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