The correct answer is + 32.5 J because heat is absorbed here by copper not evolved also after calculation we will find the H value is positive, lets calculate it:
H = m C Δt where:
m = 10 g
C = 0.13 J/g.°C
Δ t = final temperature - initial temperature = 50 - 25 = + 25 °C
so H = 10 x 0.13 x (+25) = + 32.5 J
Answer:
(a) dew condensing on a leaf
(c) ice cream melting
Explanation:
The process which can be reversed by changing the temperature , i.e. , by increasing or decreasing the temperature , is called the <u>reversible process</u> .
From the question ,
- dew condensing on a leaf is a reversible process ,
As the water on the leaf can be changed to gaseous state by increasing the temperature .
The process of condensation and evaporation are reversible of each other .
The melted ice cream can be solidified again by reducing its temperature , hence , it is a reversible process .
- an egg turning hard when boiled and the batter cooking on a hot griddle
They both are irreversible process , and by changing the temperature , we can not get back the original substance .
Answer:
0.2mol/kg
Explanation:
molality is the concentration of a solution in moles of solute per kilogram of solvent
moles of solute (NaOH) = 2moles
mass of solvent in kg. =10kg
Therefore molality. = 2moles/10 kg
=0.2mol/kg
Answer:
(C)
Explanation:
Because of the physics of it.