A mixture is a combination of two or more substances that are not chemically bonded together and can be separated by physical means. A solution, on the other hand, is a homogeneous mixture where one substance, called the solute, is dissolved in another substance, called the solvent. The solute particles are evenly distributed throughout the solvent, making it difficult to separate them by physical means.
Have you ever mixed things in the kitchen just to see what you could make? Maybe you sprinkled some cinnamon or salt in a cup of water or poured in a splash of vinegar or oil.
Maybe you called it a potion, but you were also making a solution or a mixture. You were being a chemist!
Solutions and Mixtures Facts for Kids
- A solution is a mixture where things mix well.
- Mixtures can be separated back into parts.
- Saltwater is an example of a solution.
- In a solution, what’s mixed in is called a solute.
- What mixes a solute is called a solvent.
- A salad is an example of a mixture.
- A solution looks the same everywhere.
- Lemonade is a solution of water, sugar, and lemon.
- In mixtures, you can see different parts.
- A solution can be a gas, liquid, or solid.
Solubility and Saturated Solutions
When we mix things together, we can get a mixture or a solution. A solution is a special kind of mixture where one thing, called a solute (like sugar), gets completely mixed in with another thing, called a solvent (like water). When the solute can’t be seen anymore, we say it has dissolved.
But we can’t keep adding solute forever. There’s a point when no more can dissolve. When this happens, we say the solution is saturated. So, every solution is a mixture, but not all mixtures are solutions.
Colloids and Suspensions
When we talk about mixtures, we have solutions, colloids, and suspensions. A solution completely mixes things together. In a colloid, tiny particles are spread out but don’t dissolve. Milk is a good example. But in a suspension, the particles can settle down over time, like sand in water. So, the main difference between solutions, colloids, and suspensions is how big the particles are and how well they mix together.
Homogeneous vs Heterogeneous Mixtures
When we mix things, we can make a homogeneous or a heterogeneous mixture. In a homogeneous mixture, everything is mixed up evenly, like when sugar dissolves in water – that’s called a solution. But in a heterogeneous mixture, you can see the different parts.
An example is a salad, where you can see and pick out different ingredients. So, solutions are always homogeneous mixtures, but not all mixtures are homogeneous or solutions.
Concentration and Molarity
When we mix things like salt and water, we make a solution. The amount of salt in the water is its concentration. Molarity is a special word we use to measure this concentration. For example, if we mix one unit of salt in one liter of water, that’s a one molar (1 M) solution.
So, concentration and molarity tell us how much of one thing is mixed into another. But these terms are mostly used with solutions, where everything is mixed evenly.
Chemical Reactions and Solubility Rules
Mixing things together can cause chemical reactions. Sometimes, this makes a solution, like when salt dissolves in water and splits into sodium and chloride ions. But, not everything can dissolve in water. This is where solubility rules come in, telling us what can dissolve and what can’t.
A simple rule is “like dissolves like”. So, solutions are special mixtures where things dissolve, and this often involves chemical reactions and solubility rules.
States of Matter and Solutions
When we mix things, we can have solid, liquid, or gas mixtures. A solution is a special type of mixture where something dissolves in something else, like sugar in water. This can happen in solids, liquids, or gases.
For example, different gases mix in the air we breathe, and metals can mix to make things like steel. But in a regular mixture, like ice cubes in soda, things don’t dissolve completely. So, both mixtures and solutions can be solid, liquid, or gas, but in solutions, everything is mixed evenly.
Dissolution and Precipitation
When something like salt disappears into water, that’s called dissolution, and it forms a solution. But if we add too much salt to the water, or if we cool it down, the extra salt can’t dissolve anymore. It forms solid particles that fall out of the solution, and we call this precipitation.
So, solutions are made through dissolution. But if a solution has too much solute, it can cause precipitation, turning it into a different type of mixture.
Properties of Mixtures vs. Properties of Pure Substances
When we mix things together, like sugar and water, we make a mixture, and the amount of sugar can change. But with pure substances, like water, it’s always the same and only contains H2O molecules. We can usually separate mixtures back into their parts by methods like evaporation.
But, we can’t do this with pure substances without causing a chemical reaction. So, mixtures and pure substances are different in what they contain and how we can separate them.
Distillation and Chromatography
We can separate mixtures and solutions with methods like distillation and chromatography. Distillation separates liquids like alcohol and water by using their different boiling points. Chromatography separates things like different color dyes in ink by how they move through a medium.
These methods show that while solutions are mixtures where things are mixed evenly, other mixtures may have parts that don’t mix completely.
Chemical property
Mixtures and solutions behave differently because of their chemical properties. In a solution, like salt in water, the salt splits into smaller parts, changing its properties. But in a mixture, like sand in water, the sand and water keep their original properties. So, solutions and mixtures are different because in solutions, the parts can change, but in mixtures, they stay the same.
Uniform composition
Solutions are special types of mixtures that look the same everywhere, like when sugar is dissolved in water. But some mixtures, like a salad, are different in different parts. So, solutions are mixtures, but they’re different because they are the same throughout.
Types of solution
Solutions come in different types depending on the state of the solvent. A liquid solution has a liquid solvent, like salt dissolved in water. Gaseous solutions have a gas as the solvent, such as the air we breathe. Solid solutions involve a solid solvent, like when metals mix to form alloys. So, solutions can be solid, liquid, or gas, depending on what’s being dissolved in the solvent.
Acids, Bases, and pH
In mixtures and solutions, we encounter acids, bases, and pH. Acids have a sour taste, and bases have a bitter taste and can feel slippery. The pH scale measures acidity or basicity. A pH below 7 is acidic, 7 is neutral, and above 7 is basic. Solutions can have different pH values depending on the dissolved substances. Understanding acids, bases, and pH is important in studying mixtures and solutions.
Fun Facts
- A solution happens when one substance is completely dissolved in another. If you mix sugar and water, for instance, you can make a solution.
- A mixture happens when you combine two substances but they don’t completely mix. If you added sand to a cup of water, for example, the sand would sink to the bottom.
- The substance to be dissolved is called a solute. The substance doing the dissolving is the solvent. If you added a few drops of food coloring to water, the food coloring would be the solute; the water is the solvent.
- Solutions can be a mixture of liquids, gases, and solids.
Vocabulary
Solution: A combination of two or more substances in which one substance is dissolved in another
Mixture: Two substances that are together, but not entirely combined
Learn More
Watch a 6th grade science teacher explain more about solutions.
Q and A
Question: What types of mixtures are there?
Answer: In heterogeneous mixtures, you can see all the individual materials in a substance, for example, a bowl of M and Ms or trail mix. In a homogenous mixture (or solution), you can’t see individual materials. Chocolate is a homogenous mixture. It has chocolate, sugar, milk, and other ingredients in it, but you can’t see the individual materials.
