Answer:
Economic value can be described as a measure of the benefit from a good or service to an economic agent. It is typically measured in units of currency. Another interpretation is that economic value represents the maximum amount of money an agent is willing and able to pay for a good or service.
Explanation:
The properties of aluminium include low density<span> and therefore <u><em>low </em></u></span><u><em>weight</em></u>, <u><em>high strength</em></u>, <u><em>superior malleability</em></u>, <u><em>easy machining</em></u>, <u><em>excellent corrosion resistance</em></u> and <u><em>good thermal and electrical conductivity</em></u><span> are amongst aluminium's most important properties. <u><em>Aluminium is also very easy to recycle.</em></u>
Hope this helps:D
Have a great rest of a brainly day!</span>
Answer:
+60.54 kJ/mol
Explanation:
The enthalpy of formation of a compound is the sum of the enthalpies of the formation of its constituents and the bond of them. To form a compound, energy must be lost, so, they're negative.
For SF4, the enthalpy is formed by the energy of one S, two F, and 4 S-F bond (Hb):
H = - (278.8 + 4*79.0 + 4*Hb)
-775 = -(594.8 + 4Hb)
594.8 + 4Hb = 775
4Hb = 180.2
Hb = +45.05 kJ/mol
For SF6, the enthalpy is formed by the energy of one S, six F, and 6 S--F bonds (Hb):
H = -(278.8 + 6*79.0 + 6*Hb)
-1209 = -(752.8 + 6Hb)
752.8 + 6Hb = 1209
6Hb = 456.2
Hb = +76.03 kJ/mol
Thus, the energy of S--F bond must be the average of these two:
(45.05 + 76.03)/2 = +60.54 kJ/mol
