Answer:

Explanation:
The formula for calculating the enthalpy change of a reaction by using the enthalpies of formation of reactants and products is

TiCl₄(g) + 2H₂O(g) ⟶ TiO₂(s) + 4HCl(g)
ΔH°f/kJ·mol⁻¹: -763.2 -241.828 -939.7 -92.307
![\begin{array}{rcl}\Delta_{\text{r}}H^{\circ} & = & [-939.7 + 4(-92.307)] - [-763.2 + 2(-241.828)\\& = & [-939.7 - 369.228] - [-763.2 - 483.656]\\& = & -1308.928 + 1246.856\\& = & \mathbf{-62.1}\\\end{array}\\\text{The amount of heat evolved is } \boxed{\textbf{62.1 kJ}}](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Brcl%7D%5CDelta_%7B%5Ctext%7Br%7D%7DH%5E%7B%5Ccirc%7D%20%26%20%3D%20%26%20%5B-939.7%20%2B%204%28-92.307%29%5D%20-%20%5B-763.2%20%2B%202%28-241.828%29%5C%5C%26%20%3D%20%26%20%5B-939.7%20-%20369.228%5D%20-%20%5B-763.2%20-%20483.656%5D%5C%5C%26%20%3D%20%26%20-1308.928%20%2B%201246.856%5C%5C%26%20%3D%20%26%20%5Cmathbf%7B-62.1%7D%5C%5C%5Cend%7Barray%7D%5C%5C%5Ctext%7BThe%20amount%20of%20heat%20evolved%20is%20%7D%20%5Cboxed%7B%5Ctextbf%7B62.1%20kJ%7D%7D)
Answer: HA + H2O ⇌ H3O+ + H- (option #4)
Explanation: Since the acid is weak you have to use a ⇌ (equilibrium) sign. Equilibrium is denoted in a chemical equation by the ⇌ symbol. Also, when any acid dissolves into water, it produces hydronium (H3O+ or H+). Therefore, the fourth chemical reaction is your answer.
Answer:
I'm sorry, you didn't post the pictures.
Answer:
9. 8.2x10¹⁴ Hz
Explanation:
Wavelength λ = 366 nm
Formula: Frequency = C / λ
To find the wavelength in m,
1 nm = 1.0x10⁻⁹ m
So, 366 nm = ?
= 3.66x10⁻⁷ m
Frequency = 3.0x10⁸m.s-1 / 3.66x10⁻⁷ m
= 8.2x10¹⁴ s-1