a. The unit cell is the smallest group of atom which have overall symmetry of a crystal, and from which is the entire letters can be buled built up by repetition in 3 dimensions.
b. The volume(v) of the unit cell is equal to the cell edge length (a)cubed.
c. density of polonium is 9.32g/cm3.
<u>Answer:</u> Aluminium is getting oxidized in the given chemical reaction.
<u>Explanation:</u>
Oxidation reaction is defined as the chemical reaction in which an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.

Reduction reaction is defined as the chemical reaction in which an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.

For the given chemical reaction:

The half cell reactions for the above reaction follows:
<u>Oxidation half reaction:</u> 
<u>Reduction half reaction:</u> 
As, aluminium is loosing 3 electrons to form aluminium cation. Thus, it is getting oxidized. Iron is gaining 2 electrons to form iron anion. Thus, it is getting reduced.
Hence, the oxidized species of the given reaction is aluminium.
O2 gas, where there are two Oxygen atoms which are covalently bonded together
Answer:
-125.4
Explanation:
Target equation is 4C(s) + 5H2(g) = C4H10
These are the data equations for enthalpy of combustion
- C(s) + O2(g) =O2(g) -393.5 kJ/mol * 4
- H2(g) + ½O2(g) =H20(l) = 285.8 kJ/mol * 5
- 2CO2(g) + 3H2O(l) = 13/2O2 (g) + C4H10 - 2877.1 reverse
To get target equation multiply data equation 1 by 4; multiply equation 2 by 5; and reverse equation 3, so...
Calculate 4(-393.5) + 5(-285.8) + 2877.6 and you should get the answer.