Answer:
130 g of sucrose
Explanation:
Boiling point elevation formula → ΔT = Kb . m
ΔT = Boiling T° solution - Boiling T° pure solvent → 0.39°C
0.39°C = 0.513°C/m . M
m = 0.760 mol/kg → molality = moles of solute / 1kg of solvent
Let's determine the moles of solute → molality . kg
0.760 mol/kg. 0.5 kg = 0.380 moles
If we convert the moles to mass, we'll get the answer
0.380 mol . 342.30 g/mol = 130g
Conduction: In the conduction, the heat is transferred from the hotter body to the colder body until the temperature on both bodies are equal.
In thermal equilibrium, there is no heat transfer as the heat is transferred till the temperature on the bodies are not same.
In the given problem, an iron bar at 200°C is placed in thermal contact with an identical iron bar at 120°C in an isolated system. After 30 minutes, the thermal equilibrium is attained. Then, the temperature on both iron bars are equal.Both iron bars are at 160°C in an isolated system.
But in an open system, the temperatures of the iron bars after 30 minutes would be less than 160°C. There will be heat lost to the surrounding. The room temperature is 25°C. There will be exchange of the heat occur between the iron bars and the surrounding. But It would take more than 30 minutes for both iron bars to reach 160°C because heat would be transferred less efficiently.
Answer:
Option b. Decomposition
Followed by a reduction process using charcoal
Explanation:
Lead can be obtained from lead nitrate by thermal decomposition of lead nitrate as shown below:
2Pb(NO3)2 —> 2PbO + 4NO2 + O2
The PbO obtained is reduced by charcoal(C) to obtain the metallic Pb as shown below:
2PbO + C —> Pb + CO2
Answer:
sugar and oxygen
Explanation:
In photosynthesis, solar energy is harvested as chemical energy in a process that converts water and carbon dioxide to glucose. Oxygen is released as a byproduct.
