The enthalpy change for the formation of NaCl from its elements is -411 kJ.

At constant pressure, the enthalpy change is given by ΔH = ΔU + PΔV.

The standard enthalpy change for the formation of ammonia is -92.4 kJ.

The formation of water from hydrogen and oxygen is an exothermic reaction, thus the enthalpy change is negative.

The enthalpy change for the formation of 2 moles of water is -571.6 kJ.

The enthalpy change for the formation of CO2 from carbon and oxygen is -393.5 kJ/mol.

The enthalpy change for the formation of CO2 from its elements is -393.5 kJ/mol.

The decomposition of calcium carbonate is an endothermic reaction, requiring heat input.

The standard enthalpy change for the formation of water from its elements is -241.8 kJ/mol.

The formation of ammonia from nitrogen and hydrogen is an exothermic reaction, thus the enthalpy change is negative.

The enthalpy change when 1 mole of NaCl is dissolved in water is approximately -3.87 kJ.

The condensation of water vapor to liquid water releases heat, making the enthalpy change negative.

During a phase transition at constant temperature, the change in entropy is given by ΔS = Q/T, where Q is the heat absorbed or released.

The entropy change for an ideal gas during an isothermal expansion is ΔS = nR ln(Vf/Vi).

The entropy change for an isothermal expansion is given by ΔS = nR ln(V2/V1). For 1 mole, ΔS = R ln(V2/V1).

The entropy change for the mixing of two ideal gases at constant temperature is ΔS = nR ln(2) for equal moles of each gas.

The change in entropy when heating an ideal gas at constant volume is given by ΔS = nC_v ln(T2/T1). For 1 mole, it simplifies to ΔS = R ln(T2/T1).

The change in entropy at constant volume is given by ΔS = nC_v ln(T2/T1). For 1 mole, ΔS = R ln(T2/T1).

The phase change from ice to water at 0°C involves an increase in disorder, thus resulting in a positive change in entropy.

The change in entropy for an isothermal compression is ΔS = nR ln(V1/V2). For 2 moles, ΔS = 2R ln(V1/V2), which is negative since V1 < V2.

The equilibrium constant Kc is given by the ratio of the concentration of products to reactants, raised to the power of their coefficients.

The equilibrium constant K is given by the expression K = [C]/([A]^2[B]) for the reaction 2A + B ⇌ C.

The equilibrium constant K is defined as the ratio of the concentration of products to the concentration of reactants, each raised to the power of their coefficients in the balanced equation.

Equivalent weight = molar mass / number of equivalents = 98 g/mol / 2 = 49 g.

Osmotic pressure (π) can be calculated using the formula π = iCRT. For NaCl, i = 2, C = 0.5 M, R = 0.0821 L·atm/(K·mol), and T = 298 K, resulting in approximately 24.6 atm.

The boiling point elevation is calculated using the formula ΔT_b = i * K_b * m, where i is the van 't Hoff factor.

The depression of freezing point is calculated using the formula ΔTf = Kf * m, where Kf is the freezing point depression constant and m is the molality of the solution.

The number of moles is calculated using the formula: Moles = Mass / Molar Mass.

The complex formed is Ag(NH3)2+, which is known as the diamminesilver(I) ion.

The formula of the compound formed between magnesium and chlorine is MgCl2.