Which chemical equation shows the dissociation of magnesium hydroxide? And please explain why I'm struggling with this much appreciated! Multiple Choice

Mg(OH)2 → Mg2+ + H2O + O2−

Mg(OH)3 → Mg3+ + 3OH−

Mg(OH)2 → Mg2+ + 2OH−

MgOH → Mg2+ + OH2−

Suppose you wanted to make 100 grams of water. what is the molar mass of water (h2o)?

Balance the following reaction. as2s3 + 9o2 → 2as2o3 + so2

Calculate the standard enthalpy of formation of liquid methanol, ch3oh(l), using the following information: c(graphite) + o2 latex: \longrightarrow ⟶ co2(g) latex: \delta δ h° = –393.5 kj/mol h2(g) + o2 latex: \longrightarrow ⟶ h2o(l) latex: \delta δ h° = –285.8 kj/mol ch3oh(l) + o2(g) latex: \longrightarrow ⟶ co2(g) + 2h2o(l) latex: \delta δ h° = –726.4 kj/mol