Making Solutions and Dilutions

In a concentrated solution, there is _____________.

• a large ratio of solute to solvent

• a small ratio of solute to solvent

• no solvent

• no solute

What are the units for molarity? Select TWO answers.

• mol/L

• ppm

• M

• mol/mL

• moles

Tags

NGSS.HS-PS1-5

In chemistry class, a student is suppose to prepare an acidic solution by adding 20 mL of 1M HCl to 80 mL of water. However, the student accidentally adds the 20 mL of HCl to 100 mL of water. How does this impact the concentration?

• the concentration will be higher

• the concentration will be lower

• there is not enough information to know how the concentration will be impacted

• the concentration will not change

How many moles of NaCl are found in 6.5L of a 0.40 M NaCl solution?

• 6.1 moles

• 2.6 moles

• 6.9 moles

• 16.25 moles

As we dilute a solution.....

• The volume increases and the molarity (M) increases

• The volume increases and the molarity (M) decreases

• The volume decreases and the molarity (M) increases

• The volume decreases and the molarity (M) decreases

How many mL of stock solution of 2M NaCl do you need to prepare 100 mL of 0.150M NaCl?

• 7.5 mL

• 15 mL

• 1333 mL

• 200 mL

The definition of a stock solution is ...

• a highly concentrated solution that is meant to be diluted to some lower concentration.

• moles of solute divided by liters of solvent

• a solution used to make soup and is usually either chicken or beef flavor

• a solution with less dissolved solute than a dilute solution.

What piece of glassware is best used to prepare a solution with an exact final volume?

• Test tube
• Erlenmeyer flask
• Volumetric flask
• Beaker

When preparing a solution from a solid solute, what is the next step after adding the solid to the volumetric flask?

• Add solvent to the volumetric flask until it reached the mark.

• Cap the flask and shake it vigorously.
• Add a small amount of solvent and swirl until dissolved.

• Stir the solid until it dissolves completely.

In making a dilution, after adding the stock solution to the volumetric flask, what is the next step?

• Add solvent to reach the final volume.
• Label the flask with the date.
• Measure the pH of the solution.
• Shake the flask vigorously.