The density of a 20.0% by mass ethylene glycol (C₂H₆O₂) solution in water is 1.03 g/mL. Find the molarity of the solution.

Key Concepts

Density

Density is defined as mass per unit volume, typically expressed in grams per milliliter (g/mL) or kilograms per cubic meter (kg/m³). In this context, the density of the solution helps to relate the mass of the solution to its volume, which is essential for calculating molarity. Understanding how to manipulate density allows for the conversion between mass and volume, a crucial step in determining the concentration of a solution.

Molarity

Molarity is a measure of concentration defined as the number of moles of solute per liter of solution (mol/L). It is a key concept in solution chemistry, allowing chemists to quantify how much solute is present in a given volume of solution. To find the molarity of the ethylene glycol solution, one must calculate the number of moles of ethylene glycol and divide it by the total volume of the solution in liters.

Mass Percent Concentration

Mass percent concentration is a way to express the concentration of a solution, calculated as the mass of solute divided by the total mass of the solution, multiplied by 100. In this case, the 20.0% by mass indicates that there are 20 grams of ethylene glycol in every 100 grams of solution. This concept is important for determining the amount of solute present, which is necessary for calculating molarity when combined with the solution's density.