Question

Which of the following is true regarding the concentration of solutions?

1) Percent solutions are parts per 1000 parts.
2) Molarity is one mole of solute per 1000 ml of solution.
3) To calculate molarity, one must know the atomic number of the solute.
4) To calculate molarity, one must know the atomic weight of the solvent.

Answer 1

True statement about the concentration of solutions: Molarity is the moles of solute per liter of solution, and it is calculated without needing the atomic number of the solute or the atomic weight of the solvent.

Step-by-step explanation:

Regarding the concentration of solutions, the following statement is true: Molarity is defined as the number of moles of solute per liter of solution. Percent solutions typically refer to the percent mass of the solute in the solvent and are expressed as parts per hundred, not parts per thousand.

Molarity calculations require knowledge of the molecular or formula weight of the solute, not the atomic weight of the solvent. The statement that molarity is one mole of solute per 1000 ml of solution is incorrect, as molarity is the moles of solute per liter, which is equivalent to 1000 ml, but this does not mean it is always one mole.

Lastly, calculating molarity does not depend on the atomic number of the solute; rather it depends on the number of moles of the solute and the volume of the solution.