11.2
Step-by-step-explanation
Answer:
<em>The electrons in an atom can only occupy certain allowed energy levels to a lower one</em>, the excess energy is emitted as a photon of light, with its wavelength dependent on the change in electron energy. This is why an atom can only emit specific wavelengths of light and not every possible wavelength.
Answer:
ΔH°rxn = - 433.1 KJ/mol
Explanation:
- CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
⇒ ΔH°rxn = 4ΔH°HCl(g) + ΔH°CCl4(g) - 4ΔH°Cl2(g) - ΔH°CH4(g)
∴ ΔH°Cl2(g) = 0 KJ/mol.....pure element in its reference state
∴ ΔH°CCl4(g) = - 138.7 KJ/mol
∴ ΔH°HCl(g) = - 92.3 KJ/mol
∴ ΔH°CH4(g) = - 74.8 KJ/mol
⇒ ΔH°rxn = 4(- 92.3 KJ/mol) + (- 138.7 KJ/mol) - 4(0 KJ/mol) - (- 74.8 KJ/mol)
⇒ ΔH°rxn = - 369.2 KJ/mol - 138.7 KJ/mol - 0 KJ/mol + 74.8 KJ/mol
⇒ ΔH°rxn = - 433.1 KJ/mol
Percent strength (% w/w) of a solution is defined as the amount of solute present in 100 g of the solution.
Given data:
Mass of the solute, potassium chloride = 62.5 g
Volume of water (solution) = 187.5 ml
We know that the density of water = 1 g/ml
Therefore, the mass corresponding to the given volume of water
= 187.5 ml * 1 g/1 ml = 187.5 g
We have a solution of 62.5 g of potassium chloride in 187.5 g water
Therefore, amount of solute in 100 g of water= 62.5 * 100/187.5 = 33.33
The percentage strength = 33.33 %
