Given are:
1) CuSO4 + BaCl2 ---> BaSO4 + CuCl2
2) <span>Pb(NO3)2 + 2NaCl ---> PbCl2 + 2NaNO3
3) </span><span>N2 + 3H2---> 2NH3
4)</span><span>K2SO4 + BaCl2---> BaSO4 + 2KCl
Among the 4 reactions above, the only oxidation - reduction reaction is number 3:
N2 + 3H2 ----> 2NH3
since the oxidation numbers of N and H decreased and increased, respectively making the reaction RedOx. </span>
Answer:
- 13,150.6kJ
Explanation:
CH4 + 2 O2 ------> CO2 + 2 H2O ΔH= – 890 kJ
The ΔH is enthalpy change of combustion , which is the heat is either absorbed or released by the combustion of one mole of a substance.
ΔH=−890 kJ/mol (released in the combustion of one mole of methane)
using the molar mass (in grams )of methane to get moles of sample
(237g × 1 mole of CH4)/16.04g=14.776 moles of CH4
Since 1 mole produces 890 kJ of heat upon combustion, then 14.776 moles will produce
ΔH = 14.776moles of CH4 × 890kJ/1mole of CH4
=13,150.6kJ
Therefore ΔH = - 13,150.6kJ
Silicon for example appears lustrous, but is not malleable<span> or ductile (it is </span>brittle<span> - a characteristic of some nonmetals).</span>