A 20.0 % by mass solution of phosphoric acid (H 3PO 4) in water has a density of 1.114 g/mL at 20°C. What is the molarity of this solution?

2.28 M

Explanation:

Step 1: Given data

Percent by mass (%m/m): 20.0 %

Density (ρ): 1.114 g/mL

Step 2: Calculate the percent by volume (%m/v)

We will use the following expression.

Step 3: Calculate the moles of solute in 100 mL of solution

The molar mass of phosphoric acid is 97.99 g/mol. The moles corresponding to 22.3 g are:

Step 4: Calculate the molarity of the solution

0.228 moles of solute are in 100 mL (0.100 L) of solution. The molarity of the solution is:

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.