The given solution of Mn²⁺ is 0.60 mg/mL.
Hence mass of Mn²⁺ in 5 mL of solution = 0.60 mg/mL x 5 mL = 3 mg
Molar mass of Mn = 54.9 g/mol
Hence, moles of Mn²⁺ = 3 x 10⁻³ g / 54.9 g/mol = 5.46 x 10⁻⁵ mol
The balanced equation for the reaction is,
2Mn²⁺ + 5KIO₄ + 3H₂O → 2MnO₄⁻ + 5KIO₃ + 6H⁺
The stoichiometric ratio between Mn²⁺ and KIO₄ is 2 : 5
Hence, moles of KIO₄ reacted = 5.46 x 10⁻⁵ mol x (5 / 2)
= 13.65 x 10⁻⁵ mol
Molar mass of KIO₄ = 230 g/mol
Hence needed mass of KIO₄ = 13.65 x 10⁻⁵ mol x 230 g/mol
= 0.031395 g
= 31.395 mg
≈ 31.4 mg
<span>Dry cell battery
When an automotive battery is fully charged, the sulfuric acid and water mixture will have a specific gravity of about 1.3. Specific gravity is actually the difference in the weight of water in comparison to a specific fluid. It is measured by a hydrometer. The amount of charge in the battery is normally measured by the specific gravity of the battery. The specific gravity of water is 1 and anything less than one is considered less dense while anything that has a specific gravity of more than 1 is considered more dense than water. </span>
Answer:
32g
Explanation:
potassium nitrate has solubility of about 67g per 100g of water at 40°C, which means that potassium nitrate solution will contain 67g of dissolved salt for every 100g of water.
since at this temperature, our solution contains 35g of potassium nitrate 100g of water. The solution will be unsaturated because of the less potassium nitrate.
to make saturated solution,
mass of potassuim nitrate = 67g - 35g
= 32g
which means dissolving another 32g of potassium nitrate in solution at 40
°C will make saturated solution.
