Answer:
Molar heat of solution of KBr is 20.0kJ/mol
Explanation:
Molar heat of solution is defined as the energy released (negative) or absorbed (Positive) per mole of solute being dissolved in solvent.
The dissolution of KBr is:
KBr → K⁺ + Br⁻
In the calorimeter, the temperature decreases 0.370K, that means the solution absorbes energy in this process. The energy is:
q = 1.36kJK⁻¹ × 0.370K
q = 0.5032kJ
Moles of KBr in 3.00g are:
3.00g × (1mol / 119g) = 0.0252moles
Thus, molar heat of solution of KBr is:
0.5032kJ / 0.0252moles = <em>20.0kJ/mol</em>
I think the answer is number (4)
Answer:
Gas:
- No fixed shape or volume
- Molecules are very loosely packed
- Flows in all the directions
Liquid:
- No fixed shape but has volume
- Molecules are closely packed
- Always flows from higher to lower level
E
Water is the only polar compound so I guess that must be odd one out. I’m sorry I’m of no actual help.
The statement "Although sulfuric acid is a strong electrolyte, an aqueous solution of H₂SO₄ contains more HSO₄⁻ ions than SO₄²⁻ ions is <u>True.</u> This is best explained by the fact that H₂SO₄ <u>is a diprotic acid where only the first hydrogen completely ionizes.</u>
Why?
H₂SO₄ is a diprotic acid. That means that it has <u>two hydrogen ions</u> to give to the solution. The two dissociation reactions are shown below:
H₂SO₄ + H₂O → HSO₄⁻ + H₃O⁺
HSO₄⁻ + H₂O ⇄ SO₄²⁻ + H₃O⁺
As the arrows show, the first dissociation is complete, meaning that all the sulfuric acid that is present initially is dissociated into HSO₄⁻ and H₃O⁺. However, the second dissociation is incomplete, and it's actually an equilibrium with an acid constant (Ka)of 1.2×10⁻².
That means that if the initial concentration of H₂SO₄ was 1M, the concentration of HSO₄⁻ is going to be 1M as well, but <u>the concentration of SO₄²⁻ is going to be much less than 1M</u>, according to the dissociation constant.
Have a nice day!