Answer:
Amount of water
The thermometer
Explanation
In an experiment, there is always a dependent variable and an independent variable. The independent variable is manipulated and its effect on the dependent variable is observed.
The control is that factor in the experiment that must remain constant so that effect of the independent variable on the dependent variable can be observed.
In this case, the independent variable is the amount of sodium chloride while the dependent variable is the temperature at which the solution boils.
The controls must be the amount of water which must be held constant and the same thermometer used to measure the temperature so that the effect of the amount of sodium chloride on the temperature of the solution can be studied.
Answer : The value of for this reaction is 36.18 kJ
Explanation :
First law of thermodynamic : It states that the energy can not be created or destroyed, it can only change or transfer from one state to another state.
As per first law of thermodynamic,
where,
= internal energy of the system
q = heat added or rejected by the system
w = work done
As we are given that:
q = 38.65 kJ
w = -2.47 kJ (system work done on surrounding)
Now put all the given values in the above expression, we get:
Therefore, the value of for this reaction is 36.18 kJ
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.
[Ne] 3s² 3p⁴
Not sure if that’s right