20 mL of aqueous copper (II) chloride (CuCl2) is poured into a beaker with 50 mL of sodium hydroxide and the following reaction occurs: NaOH(aq) + CuCl2 (aq) -->
Cu(OH)2(s) + NaCl(aq)
Which of the following correctly balances this equation?
2 NaOH(aq) + 2 CuCl2(aq)
--> 2 Cu(OH)2(s) + 2 NaCl(aq)
+
-->
CuCl2(aq)
NaOH(aq) +
Cu(OH)2(5)
2 NaCl(aq)
2 NaOH(aq) + CuCl2(aq)
--> Cu(OH)2(s) + 2 NaCl(aq)
2 NaOH(aq) + CuCl2(aq)
Cu(OH)2(s) + NaCl(aq)

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.

it's all four options.