In order to solve this question, you use the formula C1V1=C2V2; C1 and V1 represent the concentration and volume of the starting solution respectively, and C2 and V2 represent the concentration and volume of the final solution respectively.
In this case, C1 is 10.5, V1 is unknown, C2 is 0.98 and V2 is 3 liters.
(10.5)(x)=(0.98)(3) (divide both sides by 10.5)
X=0.28 L
This means that you will use 0.28 L of the 10.5 M solution and 2.27 L (3 L-0.28 L) of water to make 3 L of a 0.98 M solution.
Hope this helps
The bracket just separate an atom or the ion and in the above it means there are two hydroxide molecules
so bracket function is just to separate ions and molecules
hope it helps
Answer:
Vapour pressure of solution is 78.151 torr
Explanation:
Molar mass of biphenyl = 154.21 g
Molar mass of benzene = 78.11 g
19.2 g biphenyl = (19.2/154.21) moles of biphenyl = 0.125 moles of biphenyl
33.7 g of benzene = (33.7/78.11) moles of benzene = 0.431 moles of benzene
Total number of moles = (0.125+0.431) moles = 0.556 moles
Mole fraction of benzene in solution = (0.431/0.556) = 0.775
According to Roults law, vapour pressure of solution made from non-volatile solute = 
Here solute is biphenyl and solvent is benzene
So, vapour pressure of solution =
= 78.151 torr