Given :
A 250 ml beaker weighs 13.473 g .
The same beaker plus 2.2 ml of water weighs 15.346 g.
To Find :
How much does the 2.2 ml of water, alone, weigh .
Solution :
Now, mass of water is given by :

Therefore , mass of 2.2 ml of water alone is 1.873 g .
Hence , this is the required solution .
Answer : The heat of the reaction is -221.6 kJ
Explanation :
Heat released by the reaction = Heat absorbed by the calorimeter


where,
= heat released by the reaction = ?
= heat absorbed by the calorimeter
= specific heat of calorimeter = 
= change in temperature = 
Now put all the given values in the above formula, we get:


As, 
So, 
Thus, the heat of the reaction is -221.6 kJ
Answer: C= 0.406 M
Explanation:
Solution.
ν
=
0.730
m
o
l
;
ν=0.730mol;
V
=
1.8
⋅
1
0
3
m
L
=
1.8
L
;
V=1.8⋅10
3 mL=1.8L;
C=0.730mol
1.8 L=0.406 M
C= 1.8L
0.730mol =0.406M
The student made a mistake because he did not convert a unit of volume from milliliters to liters. After all, molarity is defined as the number of moles of solute per liter of solution.
First shell from the nucleus can have a maximum of 2 electrons ! hope this helped