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:
1,2,3
Explanation:
Heat gain implies that heat is absorbed by the system in order to make the stated phase transition possible.
Before a liquid changes to gas, intermolecular forces in the liquid are broken by energy supplied as heat.
Also, transition from solid to liquid requires energy to break intermolecular bonds.
Finally, sublimation requires input of energy in the form of heat.
<h2>
Answer:
</h2>
Nitrogen forms many thousands of organic compounds. Most of the known varieties may be regarded as derived from ammonia, hydrogen cyanide, cyanogen, and nitrous or nitric acid. The amines, amino acids, and amides, for example, are derived from or closely related to ammonia.
<h3>
Explanation:
</h3>
A carbohydrate has only Carbon, Hydrogen and Oxygen, with the hydrogen and oxygen in the ratio 2:1.
Examples are glucose C6H12O6 and table sugar C12H22O11
A protein is made of amino acids. Amino acids have an amino group which is −NH2.
So without nitrogen atoms the compound cannot be a protein.
Nucleic acids are organic compounds that contain carbon, hydrogen, nitrogen but they also contains phosphorus and oxygen. They are made of smaller units called nucleotides.
So;
Simple Amines are the class of organic compounds that only contains Carbon, Hydrogen and Nitrogen.
<h2>
Answer:</h2>
Average atomic mass of an element is the sum of the masses of its isotopes each multiplied by its natural abundance




