Question

Q3 enthalpy of vaporization of a substance is 8400 joule per mole and its boiling point is -173 degree Celsius the entropy change for vaporization is​

Answer 1

Answer:

We're asked to check whether a square pyramid, satisfying the following properties, really exists or not.

Since the square pyramid is made using a square of side 16 cm,

Length of base edge, \sf{a=16\ cm}a=16 cm

The triangle used to make has one side of length 16 cm, which should be attached to side of the square, so that the other sides of the triangle, measuring 10 cm each, should be slant edge of the square pyramid.

Length of slant edge, \sf{e=10\ cm}e=10 cm

Let's find the height of the square pyramid, \sf{h,}h, which is given by,

$\longrightarrow\sf{h=\sqrt{e^2-[(\dfrac{a}{2})^2+(\dfrac{a}{2})^2]}}$⟶h=

$\longrightarrow\sf{h=\sqrt{e^2-[\dfrac{a^2}{4}+\dfrac{a^2}{4}]}}$⟶h=

$\longrightarrow\sf{h=\sqrt{e^2-\dfrac{2a^2}{4}}}$⟶h=

$\longrightarrow\sf{h=\sqrt{e^2-\dfrac{a^2}{2}}}$⟶h=

Putting values of \sf{e}e and \sf{a,}a,

$\longrightarrow\sf{h=\sqrt{10^2-\dfrac{16^2}{2}}}$⟶h=

$\longrightarrow\sf{h=\sqrt{100-\dfrac{256}{2}}}$⟶h=

$\longrightarrow\sf{h=\sqrt{100-128}}$⟶h=

$\longrightarrow\sf{h=\sqrt{-28}\ cm}$⟶h=

Well, square root of a negative number is not real. This implies the square pyramid does not exist.

Hence, we can't make a square pyramid using square of side 16cm, and four triangles each with one side 16 cm and the other two sides of 10 cm each.

Answer 2

Entropy change for vaporization is​ ΔS=84Jmol⁻1K⁻¹

Explanation:

• Entropy change for vaporization is also known as the heat of vaporization or heat of evaporation​
• It is the quantity of heat absorbed if a certain quantity of liquid is vaporised.
• It is denoted by ΔH

ΔH-TΔS=0

ΔH=TΔS

ΔS=ΔH/T

where ΔH=8400joule/mole

⇒T =Boiling point is -173 degree celsius

⇒K=-173+273K

⇒K=100K temprature T

ΔS=8400/100

ΔS=84Jmol⁻1K⁻¹

Entropy change for vaporization is​ 84Jmol⁻1K⁻¹