Ametal sheet 7.5 mm thick with an area of 0.5 m2 has a temperature gradient applied across it, with the temperature on one side of the sheet fixed at 150 oc and the other at 50 oc. after a time, steady-state heat conduction is achieved. (a) plot and calculate the temperature gradient at steady state (b) add an arrow to your plot to indicate the direction of heat flow (c) calculate the heat loss through the sheet per hour if the sheet is made of aluminum (k=247 w/mk) and if the sheet is made of copper (k=398 w/mk). (d) imagine that the boundary conditions on the temperature are removed. what will eventually happen to the temperature gradient through the metal sheet? draw your answer on top of your plot from (a).

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.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

a:

by the combination of an unlimited number of elements