Chemical Change Lab Report

The experiment is to observe a variety of chemical reactions and to identify patterns in

Procedure: In this experiment, various chemicals were mixed together, to determine a reaction. Using two drops from chemical 1 and two drops of chemical two, unless otherwise stated, then recording the type of physical reaction or color changes that occurred.

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.

1. What type of macroscopic evidence for chemical change did you observe during this experiment? Give at least three different examples. (15 points) The main evidence of chemical change in this lab is the change in color, production of gas, and the production of precipitate.

A chemical reaction is when substances (reactants) change into other substances (products). The five general types of chemical reactions are synthesis (also known as direct combination), decomposition, single replacement (also known as single displacement), double replacement (also known as double displacement), and combustion. In this lab, the five general types of chemical reactions were conducted and observations were taken before, during, and after the reaction. Then the reactants and observations were used to determine the products to form a balanced chemical equation. The purpose of this lab was to learn and answer the question: How can observations be used to determine the identity of substances produced in a chemical reaction?

Aim: The aim of the lab “Chemical Equilibrium” is to observe the effects of changes in concentrations of products and reactants on the position of the equilibrium of given chemical reactions.

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.

In this experiment you will observe some physical and some chemical changes. You will observe that energy must be used to start some chemical reactions, and that it is produced in others.

The objective of this experiment will be to combine various substances, liquids and metals, and to observe their behavior when they are combined. The types of reactions observed shall determine the nature of these reactions: physical or chemical.

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.

4. The following examples do not always indicate chemical change. For example, change in color will always indicate chemical change because the color changes but it does not change the substance’s physical properties. The apparent loss in mass is a phase change; therefore the entire substance goes through a physical change. The apparent disappearance of a substance is a chemical change and will always be a chemical change because it might result of a soluble substance dissolving in a liquid and changes the entire substance in a chemical phase.

Purpose: The purpose of this experiment is to observe a variety of chemical reactions and to identify patterns in the conversion of reactants into products.

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

Many signs show that a chemical reaction has occurred. Some ways we know there is a chemical reaction are the formation of gas, formation of precipitate, change in temperature, and,or change in color. In part one of the experiment, we know there was a chemical change because of the formation of the white precipitate. We poured the ammonia and water in the flask with alum and water, forming a white, cloudy substance in between the two liquids. The white, cloudy substance between the two is liquids is also known as aluminum hydroxide. The second part of the experiment was very similar to the first, but in the second part we mixed epon salt, water, and ammonia. The precipitate formed from mixing the epson salt, water, and ammonia was called magnesium hydroxide.

An example of a chemical change that one could come into contact with daily is rust. Air and iron are the reactants in this situation while rust is the product. The chemical equation for this reaction would look roughly like this, O+FE= OFE or rust. This is clearly a chemical change because you cannot reverse it meaning you cannot take rust and pull out the iron to leave air or vise versa. All chemical changes are finite. One other example of a chemical change is the burning of any substance. For example if one were to burn a sheet of paper it would create ash. This chemical change is finite because you cannot change ash back into paper.