#### Solution concentration practice problems with answers

Concentration is the amount of solute in given solution.

### Quiz #4-3 PRACTICE: Concentration of Solutions

We can express concentration in different ways like concentration by percent or by moles. It is the amount of solute dissolves in g solvent. Example: 10 g salt and 70 g water are mixed and solution is prepared. Find concentration of solution by percent mass. We can express concentration of solutions by moles. Number of moles per liter is called molarity shown with M.

Example: Using 16 g NaOH, ml solution is prepared. Which ones of the following statements are true for this solution? Molar mass of NaOH is 40 g. Since volume of solution is mL, volume of water is smaller than mL. II is false. If we add water to solution, volume of solution increases but moles of solute does not change. Example: 4,4 g XCl 2 salt dissolves in water and form ml 0,4 molar XCl 2 solution. Find molar mass of X. Molality is the another expression of concentration of solutions. It is denoted with "m" and formula of molality is.

We find equivalent weight. Concentration with Examples Concentration Concentration is the amount of solute in given solution. Solution: Mass of solution is g before addition sugar and water.

## Concentration, Dilution, & Stoichiometry

Molar mass of NaOH is 40 g I. Concentration of solution is 2 molar II. Volume of the water in solution is ml III. If we add water to solution, moles of solute decreases. Tags: concentration concentration by mole concentration by percent equivalent molality molarity normality. Additional Information.The properties and behavior of many solutions depend not only on the nature of the solute and solvent but also on the concentration of the solute in the solution. Chemists use many different units when expressing concentration; however, one of the most common units is molarity.

Molarity M is the concentration of a solution expressed as the number of moles of solute per liter of solution:. For example, a 0. In order to calculate the molarity of a solution, you need to know the number of moles of solute and the total volume of the solution. Instead of calculating the moles of solute and liters of solution present individually, you can also string all the calculations together in one problem:.

Example: What is the molarity of a solution prepared by dissolving As you can see, both methods give exactly the same result. Choose whichever method is most comfortable for you. Serial dilutions. Search this site. Molarity M. To calculate molarity: Calculate the number of moles of solute present.

Calculate the number of liters of solution present. Divide the number of moles of solute by the number of liters of solution.

Instead of calculating the moles of solute and liters of solution present individually, you can also string all the calculations together in one problem: Divide the amount of solute by the volume of solution regardless of the initial units given. Use dimensional analysis to convert the amount of solute to moles of solute. Use dimensional analysis to convert the volume of solution to liters of solution if necessary.

The following example will illustrate both methods. Method 1: Calculate the number of moles of solute present. Method 2: Divide the amount of solute by the volume of solution regardless of the initial units given. Report abuse. Page details. Page updated. Google Sites.Answer the following to the best of your ability.

Questions left blank are not counted against you. A new page will appear showing your correct and incorrect responses. If you wish, you may return to the test and attempt to improve your score. If you are stumped, answers to numeric problems can be found by clicking on "Show Solution" to the right of the question.

Do NOT type units into the answer boxes, type only the numeric values. Do NOT use commas or scientific notation when entering large numbers. Answer all non-integer questions to at least 3 significant figures. Choose the correct name of the following solute concentration units: a.

Molarity Molality Mole fraction Percent by mass Percent by volume b. Molarity Molality Mole fraction Percent by mass Percent by volume c. Molarity Molality Mole fraction Percent by mass Percent by volume d. Molarity Molality Mole fraction Percent by mass Percent by volume e.

Molarity Molality Mole fraction Percent by mass Percent by volume a. Which of the following concentration units is not temperature-independent? Molarity Molality Mole fraction Percent by mass b. The following are mixed into a solution- 6. Liquid A is mixed with liqid B forming solution AB. When two liquids are combined to form a solution, which of the following properties of the individual liquids are always additive?

The mole fraction of compound B must be: 0. What is the molarity when What is its molarity? What is its molality? Assuming the volumes are additive, what is the final molarity of solution? Use this information to answer the questions concerning the temperature dependence of solubility: a. At what temperature are the solubility of A and B the same?

What is the solubility of both A and B at this temperature? At what temperature can 1. How many grams of B can be completely dissolved in g of water at 61 o C? How many grams of water must be added to completely dissolve 3. How many more grams of water must be added to completely dissolve all the B? How many more grams of A can be added before the solution is saturated? The solvent is:.

For each of the following questions or statements, select the most appropriate response and click its letter:. Your answers are highlighted below. Question 1. What volume of a concentrated solution of potassium hydroxide 6. Question 2. What is the concentration of an aqueous methanol solution produced when 0. Question 3. This means that:.

Question 4. How many grams of H 3 PO 4 are in mL of a 3. Question 5. How many grams of NaOH are there in Question 6. Question 7. As more salt is dissolved in water, what will happen to the boiling point of that solution? Question 8.

What is the molarity of an aqueous solution containing Question 9. What is the concentration of a sodium chloride solution prepared by dissolving 0.

Question What is the molarity of a solution prepared by diluting Once you are finished, click the button below. Any items you have not completed will be marked incorrect.Practice Questions 2. Put this information together to solve the problem, arranging the information to end up with the desired unit:. What mass of NaCl are dissolved in mL of a solution if the concentration of the solution is 0.

Because the question involves mass, we will need to know the molar mass of NaCl. Using a periodic table we find the molar mass of NaCl to be Because the question involves mass, we will need to know the molar mass of C 6 H 12 O 6. Using a periodic table we find the molar mass of C 6 H 12 O 6 to be Because the question involves mass, we will need to know the molar mass of H 2 SO 4.

Using a periodic table we find the molar mass of H 2 SO 4 to be Because the question involves mass, we will need to know the molar mass of Cu NO 3 2. Using a periodic table we find the molar mass of Cu NO 3 2 to be Final answer: 4.

Solution: 1. The question asks for concentration, which means finding molarity, or: moles solute. We are given the concentration. I suggest you rewrite the concentration as shown to the right, to better see how the units will cancel out. We are given the concentration 0. The question asks for concentration, which means finding molarity, or:.

To convert mass of ethanol to moles, we need to find the molar mass of C 2 H 5 OH using the periodic table. Molar mass is The question asks for mass, so we want to calculate grams. Because the question involves mass, we will need to know the molar mass of NaCl Using a periodic table we find the molar mass of NaCl to be The question gives us the volume in mL.

Our unit of concentration uses L, so we will convert mL into 0. Put this information together to solve the problem, arranging the information to end up with the desired unit: g.

What mass of dextrose, C 6 H 12 O 6 is dissolved in mL of 0. Because the question involves mass, we will need to know the molar mass of C 6 H 12 O 6 Using a periodic table we find the molar mass of C 6 H 12 O 6 to be A mass of 98 g of sulfuric acid, H 2 SO 4is dissolved in water to prepare a 0. What is the volume of the solution? The question asks for volume, so we want to calculate litres, L or mL.

### Chemistry 30

The concentration of the solution is:.Pharmacy Tech Study. Pharmacy Dilution Math Pharmacy Dilution Math is a process of reducing the concentration of a solution by adding more solvent. The formulas explained here are only to be used for the purpose of diluting a solution from a higher percentage to a lower percentage.

These methods are shortcuts to algebra methods and should only be used for taking the pharmacy tech test. A tech who will be compounding solutions should always use the proper algebra formula.

Click here to see the Proper Algebra Method The pharmacist hands you a 1. How much sterile water will you use? This video shows how to do the same problem, but with alligation, and basic algebra. The answer is C. If you want to cross check your answer, you could by taking this new information and doing an Alligation. This type of pharmacy tech math may be more difficult for those who have not taken algebra in school or pharmacy dilution math before.

Want to see the proper algebra way to do this problem in text? Question: The pharmacist hands you a 1. Unofficial Practice Test questions.Chapter 1 Chapter 1: The Chemical World 1. To define a solution precisely, we need to state its concentration: how much solute is dissolved in a certain amount of solvent. Words such as dilute or concentrated are used to describe solutions that have a little or a lot of dissolved solute, respectively, but these are relative terms whose meanings depend on various factors.

Concentration is the measure of how much of a given substance is mixed with another substance. Solutions can be said to be dilute or concentrated.

Solution Stoichiometry Practice Problems & Examples - Finding Molarity, Mass & Volume

A concentrated solution is one in which there is a large amount of solute in a given amount of solvent. A dilute solution is one in which there is a small amount of solute in a given amount of solvent. A dilute solution is a concentrated solution that has been, in essence, watered down. Think of the frozen juice containers you buy in the grocery store. What you have to do is take the frozen juice from inside these containers and usually empty it into 3 or 4 times the container size full of water to mix with the juice concentrate and make your container of juice.

Therefore, you are diluting the concentrated juice. When we talk about solute and solvent, the concentrated solution has a lot of solute versus the dilute solution that would have a smaller amount of solute. The terms "concentrated" and "dilute" provide qualitative methods of describing concentration.

Although qualitative observations are necessary and have their place in every part of science, including chemistry, we have seen throughout our study of science that there is a definite need for quantitative measurements in science. This is particularly true in solution chemistry. In this section, we will explore some quantitative methods of expressing solution concentration.

There are several ways of expressing the concentration of a solution by using a percentage. Each mass must be expressed in the same units to determine the proper concentration. A saline solution with a mass of g has A dextrose also called D-glucose, C 6 H 12 O 6 solution with a mass of 2. Sometimes you may want to make up a particular mass of solution of a given percent by mass and need to calculate what mass of the solute to use.

Using mass percent as a conversion can be useful in this type of problem. The appropriate conversion factor based on the given mass percent can be used follows:. To solve for the mass of NaCl, the given mass of solution is multiplied by the conversion factor. What is the amount in g of hydrogen peroxide H 2 O 2 needed to make a 6. Learning Objectives Express the amount of solute in a solution in various concentration units. Introduction Concentration is the measure of how much of a given substance is mixed with another substance.

The solution particles are closer together. The solution on the right is more dilute less concentrated. Mass Percent There are several ways of expressing the concentration of a solution by using a percentage. Using Mass Percent in Calculations Sometimes you may want to make up a particular mass of solution of a given percent by mass and need to calculate what mass of the solute to use.