March 20 and September 22
Answer:
True
Explanation:
Convection is a form of heat transfer that is predominantly common in fluids especially liquid and gas.
It occurs by the movement of a part of substance from one place to another based on density and temperature differences.
A typical convection cell is made up of a liquid that is heated. The liquid part close to the heat source becomes warmer and rises due to its low density. The part away from the heat source is more dense and begins to sink.
This analogy is commonly demonstrated in a boiling pot of water.
Answer:
The mass percentage of calcium nitrate is 31.23%.
Explanation:
Let the the mass of calcium nitrate be x and mass of potassium chloride be y.
Total mass of mixture = 19.12 g
x + y = 19.12 g..(1)
Mass of solvent = 149 g = 0.149 kg
Freezing point of the solution, = -5.77 °C
Molal freezing constant of water = 1.86 °C/m =1.86 °C/(mol/kg)
The van't Hoff factor contribution by calcium nitrate is 3 and by potassium chloride is 2.So:
i = 3
i' = 2
Freezing point of water = T = 0°C
On solving we get:
....(2)
Solving equation (1)(2) for x and y:
x =5.973 g
y = 13.147 g
Mass percent of in the mixture:
The mass percentage of calcium nitrate is 31.23%.
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