A sample of lithium was completely reacted with water. The equation for this reaction is:
2Li(s) + 2H_2O(l) → 2LiOH(aq) + H_2(g)
The aqueous lithium hydroxide solution formed has a concentration of 0.10 mol/L.
What is its concentration in g/L?
(A_r: Li = 7.0; O = 16.0; H = 1.0)
A. 240
B. 480
C. 4.8
D. 3.1
E. 2.4
The question asks us to find the concentration of a lithium hydroxide solution in g/L, given that we know the concentration in mol/L. To do this, we first need to determine the molar mass of lithium hydroxide. The molar mass of a substance is the sum of the atomic weights of all the atoms in the chemical formula of the substance.
In this case, the formula for lithium hydroxide is LiOH, which means it is made up of one atom of lithium, one atom of oxygen, and one atom of hydrogen. The atomic weight of lithium is 7.0, the atomic weight of oxygen is 16.0, and the atomic weight of hydrogen is 1.0. Therefore, the molar mass of lithium hydroxide is 7.0 + 16.0 + 1.0 = 24.0 g/mol.
Next, we need to convert the concentration in mol/L to g/L. We can do this by multiplying the concentration in mol/L by the molar mass of lithium hydroxide. In this case, the concentration is 0.10 mol/L and the molar mass is 24.0 g/mol, so the concentration in g/L is 0.10 x 24.0 = 2.4 g/L.
Therefore, the answer to the question is 2.4 g/L, which corresponds to option E.