Physical And Chemical Changes
Before we conduct these experiments there are some topics that we must discuss. As I stated in the purpose, in this lab we are going to be looking at some experiments, and we have to determine whether they are a cause of chemical or physical changes. The purpose for all the labs that we will be doing will be the same. During a chemical change a new substance is formed, it is irreversible, and it is usually accompanied by energy changes. In comparison, during a physical change no new substance is formed, it is easily reversible, and it is usually accompanied by energy changes.
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An example of an energy change would be heat or light. Just to give you can example of a chemical change this would be burning a piece of wood. This is because the wood is mixed in with oxygen to make a change. The name of the starting substances during a chemical change is reactants and the name of the new substance is the product. An example of a physical change would be water to ice, because the ice can easily be changed by into water, but by the change of temperature this physical change occurs. When mixing chemicals together it is important to understand what solvent and solute is.
Solute is the solid that is dissolved in the liquid. The name of the liquid is the solvent. It is important to know this, because in experiment one mixed solvents and solutes together quite frequently. Before conducting any experiment it is very important to take note of what type of state ones materials are in. There are three different types of states that we will look at now are Solid, Liquid, and Gas. A solid has a definite shape and is tightly packed and very close to each other that they can’t move. An example of a solid would be a desktop.
A liquid flows very easily and takes on the shape of its container. A liquids particles are less packed together compared to a solid, and are able to slide past each other and an example of a liquid would be water. The last state that we need to go over is gases. A gas is able to expand and take on the shape and volume of its container. Gas has particles very loosely collected and able to move freely with space between them, which makes it different from the other two states. An example of a gas would be oxygen.
When matter goes from a solid to a gas this is called sublimation. Not many substances can go through sublimation. The opposite of sublimation is disposition. This is when matter goes from a gas state to a solid state. These three terms are important to know, because during physical and chemical changes the state of one object often changes, (refer to page one of attachments to compare the diagrams of a solid, liquid and gas). We are going to conduct a series of eight experiments and now that we have all of this background information we will be completely ready to start.