Question

Chelsea the chemist needs to make 300.0 ml of 2.50 m HNO₃ solution. she has 15.0 m (concentrated) HNO₃ solution available.

combine _____ of 15.0 m HNO₃ with ____distilled water to make 300.0 ml of 2.50 m HNO₃ solution.

Answer 1

To prepare 300.0 ml of a 2.50 M HNO₃ solution, Chelsea needs to combine 50.0 ml of 15.0 M HNO₃ with 250.0 ml of distilled water. She must add the acid to the water for a safe dilution process.

Step-by-step explanation:

To dilute Chelsea's 15.0 M concentrated HNO₃ solution to make 300.0 ml of a 2.50 M HNO₃ solution, we first need to use the dilution equation C1V1=C2V2, where C1 and V1 are the concentration and volume of the concentrated solution, and C2 and V2 are the concentration and volume of the diluted solution respectively. Using this equation, we calculate the necessary volume of the concentrated acid to use before adding distilled water to reach the final volume of 300.0 ml.

First, rearrange the dilution equation to solve for V1: V1 = (C2V2)/C1. Plugging in the values gives us V1 = (2.50 M × 300.0 ml) / 15.0 M. Calculating V1 gives us 50.0 ml. Chelsea will need to combine 50.0 ml of the 15.0 M HNO₃ with 250.0 ml of distilled water to achieve her desired 2.50 M concentration in a 300.0 ml solution.

Important Considerations

When performing a dilution, it's vital to add the acid to the water rather than the other way around to ensure safety. The water provides a larger heat capacity to absorb the heat generated when the acid is added.