2: Solutions 2.01: Solutions: Wiva k12 Chemistry

saturated

a solution in which the greatest possible amount of solute is dissolved .

supersaturated

a solution, under specific conditions, that contains more solvent than exists in a saturated solution at room temperature

solute

a substance that dissolves in solvent

solvent

a substance, usually liquid, that can dissolve other substances

Salt water contains sodium chloride dissolved in water. Which of the following is a mass/volume measure of the concentration of the salt? a.) 35 g/L b.) 35 mL/100L c.) 35% d.) 35 mL/L

a.) 35g/L

Why can you make a cup of hot tea sweeter than a cup of iced tea? a.) Iced tea is capable of dissolving more sugar than hot tea. b.) Hot tea is capable of dissolving more sugar than iced tea. c..) Hot tea does not become saturated. d.) Iced tea is already saturated.

b.) Hot tea is capable of dissolving more sugar than ice tea

1. Which of these terms best describes a solution in a typical kitchen that has as much dissolved solute as it can hold? a.) supersaturated b.) saturated c.) dilute d.) concentrated

b.) saturated

An unopened can of soda has more carbon dioxide inside than would be possible if the can were opened. Which of the following terms best describes the solution of soda and gas? a.) saturated b.) supersaturated c.) dilute d.) concentrated

b.) supersaturated

Which of the following terms best describes any solution? a.) dilute b.) saturated c.) homogeneous d.) heterogeneous

c.) homogeneous

solution

A homogenous mixture in which the substances are completely and evenly mixed, down to their individual molecules

A solution is made of a solute and a solvent, and it occurs in specific concentrations.

A solution is a homogeneous mixture of a solute dissolved in a solvent. A solution can be described as dilute or concentrated, depending on the amount of solute relative to the amount of solvent. These amounts, called concentrations, can be described as percentages, or, for solutions involving solids and liquids, as mass/volume ratios. The amounts can also be described in terms of volume/volume ratios when the solution is composed of liquids.

A solution can be described in qualitative terms.

As you probably know, sugar water will be too sweet if too much sugar is added to the solution. When making sugar water, you have to keep in mind the amounts of the solute and the solvent. If you are discussing the amount of solute and the amount of solvent, you are talking about the concentration of a solution. Weak, not very sweet, sugar water is said to have a relatively low concentration of solute—in this case, the sugar. Strong, sweet sugar water has a relatively high concentration of sugar. A solution with a smaller amount of solute is a dilute solution. One with a greater amount of solute is called a concentrated solution. The terms dilute and concentrated are relative.

A solution is composed of a solute and a solvent.

In a solution, one substance is mixed with another substance. The substance that is broken down, or dissolved, is called the solute. The substance in which it is dissolved is called the solvent. In a sugar solution, sugar is dissolved in water. The sugar is the solute, and the water is the solvent. In salt water, a solid, sodium chloride, is dissolved in water. Water is the solvent; sodium chloride is the solute. Soda is also a solution. In soda, the solute is a gas, carbon dioxide, and it is dissolved in a liquid solvent, water.

A solution is a homogeneous mixture.

Solutions are composed of a solute dissolved in a solvent. Solutions can be described as being dilute or concentrated. Examples of solutions are all around you. As you will see in this lesson, there are many properties that can be ascribed to solutions.

Unit Introduction: Solutions

Solutions, which are important parts of chemistry and of everyday life, demonstrate how matter interacts. Most drinks are made of water with sugars and other solids dissolved into them. How do solids dissolve in the water? What factors speed up or slow down the dissolving process? Solutions are all around, from a glass of lemonade to seawater. In this unit, you will learn the definition of a solution and much about the chemistry of solutions.

A solution can also be described in quantitative terms.

The terms dilute and concentrated are qualitative, nonnumerical measures of concentration. For chemistry work, the concentration of a solute in a solvent is often expressed in terms of a percentage—a numerical or quantitative measure. For example, a 3% saltwater solution contains 3% salt and 97% water. There are other, more informative ways to express the concentration of a solution. If 6 grams of salt is added to 1 liter of water, the concentration can be written as a mass/volume ratio: 6.0 g/L.

Sometimes a solution may become saturated.

Try this simple experiment: Take a small amount of room-temperature water. Add sugar a teaspoon at a time, and, as you go along, stir to dissolve the sugar. As you keep adding sugar, you will notice that a point will be reached where no more sugar can dissolve. The solvent, water, cannot hold any more of the sugar in solution. This solution is now said to be saturated. A saturated solution is one in which the solution cannot possibly dissolve more solute under the existing conditions. Temperature plays a role in the ability of a solution to become saturated. If you were to try the same experiment with warm water and sugar, you would find that the solution could hold more solute. Temperature can influence the ability of a solution to hold solute.

Solutions are all around.

What do seawater, the blood coursing through your veins, an ice-cold glass of lemonade, and a powerful acid have in common? All of these substances are solutions. A solution is a homogeneous mixture of two or more substances in one physical state. Homogeneous mixtures do not contain parts that are visibly distinguishable. Think about lemonade. You can try all day, but the chances of identifying individual particles of sugar, water, and lemon juice molecules in that substance are low. Lemonade is a homogeneous mixture, a solution.

It is possible for a solution to become supersaturated under the appropriate conditions.

What might happen when a bottle of soda or seltzer is uncapped? It is quite possible that when the pressure is released, the soda will effervesce out of the bottle as the carbon dioxide in the solution rushes to escape. That soda or seltzer has been put under great pressure—and then sealed. Carbon dioxide has been forced into the soda. In fact, the conditions of high pressure allow more carbon dioxide to be pushed into the solution than would be possible under room conditions. In other words, the soda solution is supersaturated with the solute. And when the pressure is released, the gaseous solute rushes out, sometimes creating a messy geyser of soda.

Solutions with a liquid solute and a liquid solvent are described by volume/volume ratios.

When a solid solute is dissolved in a liquid solvent, the concentration can be described conveniently in terms of mass/volume such as g/L. If two liquids form a solution, though, the solution is best described in terms of volume/volume. Common rubbing alcohol, for example, is typically a 70% solution of isopropyl alcohol and water. This means that there are 70 mL of isopropyl alcohol for every 100 mL of solution—that is, in 100 mL there are 70 mL of alcohol and 30 mL of water.

Solutions can involve solids, liquids, and gases.

You might think that all solutions are solids dissolved in liquids, but in fact there are a number of solutions that involve other phases of matter. This table has examples of different kinds of solutions. There are solids, liquids, and gases as both solvents and solutions.