I think it is the third statement
‘A unit is made up of two or more atoms’
Explanation:
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Answer:
The heat of reaction when hydrogen and oxygen combine to form water is :
<u>C. 571.6 kJ</u>
Explanation:
Enthalpy Change = The enthalpy change for the formation of 1 mole of the substance from their standard state is called the enthalpy of formation.
This is intensive quantity as it is fixed for 1 mole .
Intensive properties = Those properties which are independent on the amount of the substance are intensive properties.
The value of these quantities does not get halve if you divide the substance into two equal parts. example , density, refractive index.
However , the enthalpy of reaction is extensive. Because on increasing the amount the value of the enthalpy also get doubles
Hence for this reaction :

Its value is -285.8 kJ for 1 mole
And here two moles are present . so the value of molar enthalpy is:
-285.8 x 2 = -571.6 kJ
= k
<u>Explanation:</u>
The relation between volume, V of gas and Temperature, T of a gas is related by Charles Law.
This law states that the volume of a given amount of gas held at a constant pressure is directly proportional to the Kelvin temperature
Thus,
= k
where k is a constant
Therefore,
=
=
...
This shows, as the volume of a gas goes up, the temperature also goes up and vice-versa.