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
I turned in this exact assignment today haha
the blood vessels dilate to draw body heat away from the body and towards the surface of the skin
sweat glands release sweat, when sweat evaporates it releases heat
Answer:
Explanation:
How many mols do you have?
1 mol = 6.02 * 10^23 atoms
x mol = 6.25 * 10 ^32 atoms
1/x = 6.02*10^23 / 6.25 * 10^32 Cross multiply
6.02 * 10^23 * x = 1 * 6.25 * 10^32 Divide by 6.02 * 10^23
x = 6.25 * 10*32/ 6.02 ^10^23
x = 1.038 * 10^9 mols which is quite large.
Find the number of grams. (Use the value for copper on your periodic table. I will just use an approximate number.)\
1 mol of copper = 63 grams.
1.038 * 10^9 mols of copper = x
1/1.038 * 10^9 = 63/x Cross multiply
x = 1.038 * 10^9 * 63
x = 6.54 * 10^10 grams of copper.
Answer:
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Explanation: