13.4 billion years is 3 times of the half-life, 4.47 billion years. So the Uranium-238 will go through three times of half decay. So the remain percentage will be 50%*50%*50%=12.5%.
Answer:
2.48 mol/L.
Explanation:
- The molarity of the solution can be expressed as <em>the number of moles of solute in 1.0 liter of the solution, </em>(M = n / V).
- It is also can be calculated from the relation:
<em>M = (mass / molar mass) solute x (1000 / V of solution)</em>
The solute is toluene and the solvent is benzene.
mass of toluene (solute) = 57.1 g,
molar mass of toluene (solute) = 92.14 g/mol.
volume of the solution = 250 ml.
∴ M = (mass / molar mass) solute x (1000 / V of solution) = [(57.1 g / 92.14 g/mol) x (1000 / 250 ml)] = 2.48 mol/L.
A rock's composition is not changed by mechanical weathering. Only the size of the fragments decreases. ... Mechanical weathering breaks rocks down into smaller fragments, and increases the surface area of the over all material. By increasing the surface area, chemical processes may act more easily upon the rock surface.
C) volume
.........
The volume of gas depends on e.g. temperature and pressure.
