!!!!HURRY!!!! What reaction is endothermic?
1 answer:
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Answer : The ages of the brother and sister are, 10 and 16 years respectively.
Solution :
Let the age of brother be 'x' and the age of sister be 'y'
There are two equations formed which are,
x + y = 26 ..........(1)
3y - 4x = 8 ..........(2)
First we have to multiple equation (1) by 4 and then added equation (1) and (2), we get the value of 'y'.
Now put the value of 'y' in equation (2), we get the value of 'x'
3(16) - 4x = 8
4x = 40
x = 10
The age of brother = x = 10 years
The age of sister = y = 16 years
Therefore, the ages of the brother and sister are, 10 and 16 years respectively.
Answer : The freezing point of the solution is, 260.503 K
Solution : Given,
Mass of methanol (solute) = 215 g
Mass of water (solvent) = 1000 g = 1 kg (1 kg = 1000 g)
Freezing depression constant =
Formula used :
where,
= freezing point of water =
= freezing point of solution
= freezing point constant
= mass of solute
= mass of solvent
= molar mass of solute
Now put all the given values in the above formula, we get
By rearranging the terms, we get the freezing point of solution.
Therefore, the freezing point of the solution is, 260.503 K