Answer:
8.55 × 10²⁴ Ions
Explanation:
Ammonium Chloride is an ionic compound which contains a monatomic anion (Cl⁻ ; Chloride) and a polyatomic cation (NH₄⁺ ; Ammonium).
Hence, when added in water Ammonium Chloride ionizes as;
NH₄Cl → NH₄⁺ + Cl⁻
Hence, we can say that it produces two ions when dissolved in water.
Also,
We know that 1 mole of any substance contains exactly 6.022 × 10²³ particles which is also called as Avogadro's Number. So in order to calculate the number of ions contained by 7.1 moles of NH₄Cl, we will use following relation to first calculate the number of molecules as;
Moles = Number of Molecules ÷ 6.022 × 10²³ Molecules.mol⁻¹
Solving for Number of Molecules,
Number of Molecules = Moles × 6.022 × 10²³ Molecules.mol⁻¹
Putting values,
Number of Molecules = 7.1 mol × 6.022 × 10²³
Number of Molecules = 4.27 × 10²⁴ Molecules
So,
As,
1 Molecule of NH₄Cl contained = 2 Ions
So,
4.27 × 10²⁴ Molecules of NH₄Cl will contain = X ions
Solving for X,
X = 2 Ions × 4.27 × 10²⁴ Molecules / 1 Molecule
X = 8.55 × 10²⁴ Ions
The concentration of solution in M or mol/L can be calculated using the following formula:
.... (1)
Here, n is number of moles and V is volume of solution in L.
The molecular formula of potassium sulfate is 
thus, there are 2 moles of potassium in 1 mol of potassium sulfate.
1 mol of potassium will be there in 0.5 mol of potassium sulfate.
Mass of potassium is 4.15 g, molar mass is 39.1 g/mol.
Number of moles can be calculated as follows:
Here, m is mass and M is molar mass
Putting the values,
Thus, number of moles of will be 
.
The volume of solution is 225 mL, converting this into L,
Thus,
Putting the values in equation (1),
Therefore, concentration of potassium sulfate solution is 0.236 M.
Answer:
3.43×10¹ mol
Explanation:
Given data:
Initial number of moles = 12.4 mol
Initial volume = 122.8 L
Final number of moles = ?
Final volume = 339.2 L
Solution:
The number of moles and volume are directly proportional to each other at same temperature and pressure.
V₁/n₁ = V₂/n₂
122.8 L/ 12.4 mol = 339.2 L / n₂
n₂ = 339.2 L× 12.4 mol / 122.8 L
n₂ = 4206.08 L.mol /122.8 L
n₂ = 34.3mol
In scientific notation:
3.43×10¹ mol
