Contains only Carbon and Hydrogen.
(3) CH3CH3
The
combustion of heptane (C7H16) in oxygen spontaneously occurs. The products of
the reaction are carbon dioxide and water vapor. The balanced chemical equation
is 7H16 + 11O2 → 7CO2 + 8H2O H
= –2877.5 kJ.
Why can physical changes separate the components of a mixture but not the components of a compound?
Several types of mixtures can be separated by physical means. Heterogeneous mixtures imply the different parts are not equally distributed, much like how on a pizza the toppings are not located in the crust. A homogeneous mixture is one where the components are equally mixed, such as orange juice or lemonade (excluding the pulp).
A common heterogeneous example is to separate oil from water by placing the mixture into a separation funnel and draining one level of liquid out. You then have the two separate components. Basically, if you can see the different layers in a mixture, you can physically remove them by either picking out the solids (either with your hands or running the mixture through filter paper) or for liquids using the funnel.
a) First, to get ΔG°rxn we have to use this formula when:
ΔG° = - RT ㏑ K
when ΔG° is Gibbs free energy
and R is the constant = 8.314 J/mol K
and T is the temperature in Kelvin = 25 °C+ 273 = 298 K
and when K = 4.4 x 10^-2
so, by substitution:
ΔG°= - 8.314 * 298 *㏑(4.4 x 10^-2)
= -7739 J = -7.7 KJ
b) then, to get E° cell for a redox reaction we have to use this formula:
ΔE° Cell = (RT / nF) ㏑K
when R is a constant = 8.314 J/molK
and T is the temperature in Kelvin = 25°C + 273 = 298 K
and n = no.of moles of e- from the balanced redox reaction= 3
and F is Faraday constant = 96485 C/mol
and K = 4.4 x 10^-2
so, by substitution:
∴ ΔE° cell = (8.314 * 298 / 3* 96485) *㏑(4.4 x 10^-2)
= - 2.7 x 10^-2 V
Hydrogen
Helium
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Sodium
Magnesium
Aluminum
Silicon
Phosphorus and
Sulfur
