Answer:
There is one single covalent bond between two carbon atoms.
Explanation:
We know that sharing of electrons form covalent bonds.
If we look upon K,L,M ,N shells of the carbon and hydrogen atoms.
We found that Hydrogen is having only
electron in K shell.
And Carbon on the other hand is having
electrons in K shell and
electrons in L shell.
So carbon have
valence electrons,and it can share
bonds with any relevant atom to complete its octet.
And Hydrogen requires
electron to complete its doublet.
Alkane general formula 
For ethane 

Carbon atom is shared by
Hydrogen.
The remaining one electron
of carbon will be shared with another carbon atom.
An image of the sharing of electrons attached below,
Hence we have only
covalent bond between the two.
Answer:
If your asking how much the reactions weigh separately than it should be 25
Explanation:
25 +25=50
Answer : The vapor pressure of propane at
is 17.73 atm.
Explanation :
The Clausius- Clapeyron equation is :

where,
= vapor pressure of propane at
= ?
= vapor pressure of propane at normal boiling point = 1 atm
= temperature of propane = 
= normal boiling point of propane = 
= heat of vaporization = 24.54 kJ/mole = 24540 J/mole
R = universal constant = 8.314 J/K.mole
Now put all the given values in the above formula, we get:


Hence, the vapor pressure of propane at
is 17.73 atm.
4-ethyl-3-methyl 1 hexane
Answer:
The reaction is exothermic (option 4)
Explanation:
P4 + 5O2 → P4O10 + 712 kcal
In chemical reactions heat can be absorbed or released:
⇒in the first case, when heat is absorbed, this is called an endothermic reaction. The products have more energy than the reactants. The reaction requires or absorbs energy from it's surroundings. That means that in this reaction energy , in the form of heat, will be absorbed by the reactants.
⇒ when heat is released, this is called an exothermic reaction. The reactants have more energy than the products. The reaction gives or releases energy to it's surroundings. That means that in this reaction energy , in the form of heat, will be released by the reactants.
in the case of P4 + 5O2 → P4O10 + 712 kcal
We notice that on the right side, which is the product side, there is a positive amount of energy. This means that the energy is released by the the reactants, in this reaction. <u>The reaction is exothermic.</u>
.