The romans used calcium oxide, cao, to produce a strong mortar to build stone structures. calcium oxide was mixed with water to give calcium hydroxide, which reacted slowly with carbon dioxide in the air to give calcium carbonate. ca(oh)2(s) + co2 → caco3(s) + h2o(g) calculate the standard enthalpy change for this reaction. kj/mol-rxn what is the change in enthalpy if 3.50 kg of calcium hydroxide reacts with a stoichiometric amount of carbon dioxide? kj

ΔH°rxn = -68.7 kJ/mol

ΔH = -3249.5 kJ

Explanation:

The standard enthalpy change of the reaction (ΔH°rxn) can be calculated by the standard enthalpy of formation of the compounds (H°f), which can be found in thermodynamics tables.

H°f, Ca(OH)₂(s) = -986.6 kJ/mol

H°f, CO₂(g) = -393.5 kJ/mol

H°f, CaCO₃(s) =-1207.0 kJ/mol

H°f, H₂O(g) = -241.8 kJ/mol

ΔH°rxn = ∑n*H°f, products - ∑n*H°f,reactants (where n is the number of moles in the balanced equation).

ΔH°rxn = (-241.8 - 1207.0) - (-393.5 - 986.6)

ΔH°rxn = -68.7 kJ/mol

The molar mass of calcium hydroxide is 74 g/mol (Ca = 40 g/mol, O = 16 g/mol, and H = 1 g/mol), so the number of moles, is the mass (3500g) divided by the molar mass:

n = 3500/74 = 47.3 moles

The change in enthalpy is the standard enthalpy of the reaction multiplied by the number of moles of the limiting reactant. Because stoichiometry is 1:1, and they have the same amount of moles, there's no reactant in excess:

ΔH = -68.7 * 47.3

ΔH = -3249.5 kJ

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.

"hydrogen bonding is the attraction of h atoms in the water molecule (slight + charge) to o atoms in a neighboring water molecule (slight - charge); it is a weak interatomic force. but it is still strong enough to the water molecules "stick" together."