Chemical Change

One of the signs of a chemical change is that sound is produced. The oxygen, fire and hydrogen react together, creating a popping noise (this is the hydrogen combusting).

What is the appearance of reactant, Evidence of chemical reaction, and properties of a product?

A physical change includes a change in the material without affecting its composition, such as the physical state change. However, a chemical change includes the change in the composition of the substance. The change in color, formation of a gas or a solid product, and the production of energy are the evidences of a chemical reaction, thus, of a chemical change.

A physical change is one that affects only the physical properties of a substance, while a chemical change alters a substance at the molecular level.

Hypothesis: If we use these materials and use magnets, water, burners, and filters on the mixtures and elements given we should determine what kind of effect these materials given will have on these mixtures and elements, physical or chemical.

There was an assortment of different changes indicating that chemical changes were taking place such as change in color or chemicals bubbling when combined with another chemical.

The objective of the experiment was to observe different reactions with different chemicals. The experiments emphasized on the chemical changes occurring in acids and bases as well as color changes and bubble formations. The experiments allowed for a better understanding of the undergoing chemical changes in mixtures. Some mixtures instantly changed colors while others were transparent or foggy. Some mixtures produced thick color that created solids called precipitates. Mixtures KI + Pb(NO3)2 and NaOH + AgNO3 both produce noticeable precipitates after a while. It was interesting to see the different acidic and base reactions like the fuchsia color formation in NaOH + phenolphthalein.

For example, in the experiment when I poured Hydrochloric acid in a test tube and then one magnesium ribbon, the substances started to bubble. Other than that, when I took the wooden split and lit it, I burned the green paper and it changed brown around the edges of the paper.

A chemical change is a change that alters the identity of a substance. A chemical change can be identified by five things: change in mass, formation of a precipitate, release of heat and/or light, color change, or giving off gas.

1. What type of macroscopic evidence for chemical change did you observe during this experiment? Give at least three different examples.

Chemical changes are often accompanied by physical changes. Three that you should not see in this lab are changes in temperature, presence of a flame, and evolution of light, as when as firefly glows. Three physical changes that indicate a chemical change may have occurred (and that may be seen in this lab) are:

This is a chemical change because a new color is created and it is exciting the electrons. Burning is a chemical reaction because there is a new substance being created. There is also a color change and that is another way to tell that it was a chemical reaction. A new substance was made this is why it was a chemical change. If you take ice for example and melt it turns into a liquid. This is not a chemical change because it is still water just in a different form nothing new is created. Unlike when the salt solutions are burned and something totally new is created/

Chemical reactions make new things by rearranging other things. In a chemical reaction, the main change that occurs relates to the way atoms are bonded to each other, in order to change those connections, bonds must be broken and new bonds be formed.

A few more important terms to keep in mind when doing a lab with chemical and physical changes are

A chemical reaction is a process in which elements or compounds react with one another to create new or different substances. There are two parts to a reaction. Those two parts are the products and the reactants. The reactants are the chemicals or chemical compounds that are going through the reaction itself. The products are chemical elements or chemical compounds that are produced as a result of the reactant or reactants reacting. There are four key indications that there’s a chemical reaction is taking place. Those four signs include a change in color and/or odor, formation of a precipitate or a gas, the release or absorption of energy (light, heat, electricity), and if the reaction is irreversible. Along with this information, there are ways to predict the products of a reaction.