What is a mixture?
A mixture is a combination of two or more substances that are not chemically combined. The ingredients of a mixture retain their chemical properties and can be physically separated from each other. An example of a mixture is salt dissolved in water. Both the water and the salt retain their chemical properties, and the salt can be removed from the water by boiling the water. Mixtures can be divided into two groups: homogeneous and heterogeneous. Homogeneous mixtures consist of the same relative amounts of each substance throughout the mixture. The saltwater that is produced when salt is dissolved in water has the same proportions of salt and water at every point in the mixture. A heterogeneous mixture is a mixture in which the proportions of the substances are not constant throughout the mixture; that is, there are different amounts of each substance at different points in the mixture. An example of a heterogeneous mixture is clam chowder. At the surface of the chowder there is more broth and fewer clams, but at the bottom there are more clams and less broth.
What is the difference between a solution, colloid, and suspension?
A solution is simply a homogeneous mixture. A solution consists of the substance that is referred to as the solute being mixed into another substance, called the solvent. When salt is mixed with water, the salt is the solute and the water is the solvent. The components of solutions are either atoms, molecules, or ions. A colloid is similar to a solution, but is made up of particles that are bigger than the atoms, molecules, or ions that make up a solution. Like a solution, a colloid is homogeneous. A suspension is a heterogeneous mixture where the substances that make up the mixture can be distributed throughout the substance evenly if it is shaken, but will eventually settle and separate into the different substances. The components of suspensions are particles that are bigger than the components of solutions or colloids.
How are saturated and unsaturated solutions different?
An unsaturated solution is a solution that can dissolve more solute if more is added. A saturated solution is a solution that has dissolved as much solute as possible, and if more solute is added, it will not dissolve.
What is an ion?
An ion is an atom or molecule in which the number of protons and the number of electrons are not equal. If there are more protons than electrons, then the atom or molecule has an overall positive charge. If there are more electrons than protons, the atom or molecule has an overall negative charge.
What is the process of disassociation?
Disassociation is the process of an ionic compound breaking down into simpler parts.
What is the difference between miscible and immiscible substances?
If two substances are miscible, it means that they will mix evenly with each other and form a homogeneous mixture. If two substances are immiscible, they will form a heterogeneous mixture. Alcohol and water are miscible because they form a homogeneous mixture when mixed. Oil and water are an example of immiscible substances because they form a heterogeneous solution when mixed, as the oil will eventually settle above the water.
What is the rule for whether substances will or will not form a solution?
Some molecules are arranged in such a way that one end of the molecule has a positive charge and the other end has a negative charge. These molecules are referred to as polar molecules. Molecules that are not arranged like this are called non-polar molecules. Generally, polar solutes will only dissolve in polar solvents, and non-polar solutes will only dissolve in non-polar solvents.
What is dynamic equilibrium?
Imagine a saturated salt solution, where no more salt seems to dissolve. It appears static, but at the microscopic level, a dynamic equilibrium exists. Salt crystals constantly dissolve into ions (dissolution), while simultaneously, dissolved ions rejoin the crystal lattice (crystallization).
These opposing processes occur at equal rates, meaning the net amount of dissolved salt remains constant. This dynamic balance is crucial for understanding solubility and precipitation. Factors like temperature and the presence of common ions can shift this equilibrium, affecting the amount of solute in solution.
What is the heat of solution?
When a solute dissolves in a solvent, the enthalpy change is known as the heat of solution. This process involves overcoming the attractive forces between solute particles in the crystal lattice and forming new attractive forces between solute and solvent particles. The energy required to break the crystal lattice is termed crystal lattice energy, while the energy released during the interaction of solute and solvent particles is known as solvation energy.
The heat of solution is the net energy change resulting from the balance between these two opposing energetic processes. If the crystal lattice energy exceeds the solvation energy, the dissolution process is endothermic, absorbing energy from the surroundings and resulting in a decrease in temperature. Conversely, if the solvation energy is greater than the crystal lattice energy, the process is exothermic, releasing energy to the surroundings and causing an increase in temperature. This principle underlies the function of instant hot and cold packs, which utilize carefully selected solutes to manipulate the heat of solution for therapeutic purposes.
Here are some definitions to help you in your Grade 3-5 Lesson 1 investigation.
States of Matter - the ways that matter can exist. The main phases of matter are solid, liquid, gas, and plasma.
Solution - the combining of two or more substances that appears to be the same throughout
Mixture - the combining of two or more substances. If the two substances appear the same throughout, they are a solution. If they do not appear the same throughout, they are not a solution, but instead a different type of mixture.
Separation - to pull apart or divide
Solutions are just one of the various types of mixtures. Mixtures are all around you. From the pepperoni pizza you eat to the gold jewelry you wear. In fact, your body is a mixture of various substances. In this module, your challenge is to mix together various substances and find out which ones form solutions. Are you ready to find all of the problem’s...answers? Now that’s funny because you thought I was going to say solutions. Anyway, let’s get started.
