Answer:
20.9%
Explanation:
- The percentage by mass of solution is given by dividing the mass of solute in grams by the mass of solution in grams then multiplying it by 100%.
% Mass of solution = mass of solute/mass of solution × 100%
= (27.0 g/ 129.0 g) × 100%
= 20.93%
= 20.9%
Se2- has 34 protons and 36 electrons so it gets a 2- charge.
Answer:
HNO₃.
Explanation:
- It is known that acids decrease the pH of the solution, while bases increase the pH of the solution.
So, HF and HNO₃ decrease the pH of the solution as they produce H⁺ in the solution.
While, KOH and NH₃ increase the pH of the solution as they produce OH⁻ in the solution.
HNO₃ will decrease the pH of the solution greater than HF.
- Because HNO₃ is strong acid that decomposes completely to produce H⁺ more than the same concentration of HF that is a weak acid which does not decomposed completely to produce H⁺.
The heat required to completely melt the given substance, platinum, we just have to convert first the given mass in mole and multiply the answer to its molar heat of fusion..
Hf = mass x (1/molar mass) x molar heat of fusion
Hf = (85.5 g) x (1 mole/195.08 g) x 4.70 kcal/mol
Hf = 2.06 kcal
