HELP HELP IM FAILING PLZ HELP ME What is the formula mass of calcium nitrate tetrahydrate (Ca (NO3)2 · 4H0]?
Be sure to add the water of hydration, which is the 4H2O part (water surrounding the calcium
nitrate).

102 g/mol
164 g/mol
174 9/mol
236 g/mol

236 g/mol

Explanation:

This question is asking to calculate the molar mass/formula mass of calcium nitrate tetrahydrate with the chemical formula: Ca(NO3)2 · 4H20. This is done as follows:

Atomic mass of the constituent elements are as follows:

Ca = 40

N = 14

O = 16

H = 1

Hence, in Ca(NO3)2 · 4H20.

= 40 + {14 + 16(3)}2 + 4 {1(2) + 16}

= 40 + {14 + 48}2 + 4{2 + 16}

= 40 + {62}2 + 4{18}

= 40 + 124 + 72

= 236

Hence, the molar mass of Ca(NO3)2 · 4H20 is 236g/mol.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.