General Chemistry Lab Report

3. Turned off the laboratory burner and observed the properties of the product in the evaporating dish.

The Purpose of this experiment is to make the observation about a Chemical system and record exactly what was seen, paying attention to details. Then to design other experiments that will allow determination of which substances that are responsible for each of either the change in temperature, production of a precipitate , production of gas, distinct odor, and color change. Pre-Lab questions : There are 4 chemicals involved in this reaction. Name Them.

The purpose of this particular lab was to experiment and identify the chemical and physical changes throughout the experiment.

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.

When the zinc was dropped in the hydrochloric acid, the substance began bubbling vigorously, forming a precipitate. Eventually, the zinc dissolved completely. After the lit wooden splint broke the surface of the test tube, there was a loud popping noise. The gas that was released was hydrogen from the acid and the popping noise was a result of the Hydrogen being burned up by the fire creating a small explosion. Two chemical changes occurred in this test: one with the formation of a precipitate (a textbook sign of a chemical change), and the other when the explosion

Procedure: Filled each test tube with substances provided and subjected them to various conditions. These conditions included, heat, cold water, hot water, acid and basic additions and tested on litmus paper. The reactions were observed and documented at each step.

In part 1, the precipitate that forms is a aluminum hydroxide and in part 2 it is magnesium hydroxide. A precipitate is an insoluble solid that emerges from a liquid solution. When the emergence of the insoluble solid from solution happens, it is called precipitation. The property change in the reactants of the lab are when the water, alum, ammonia, react and create the aluminum hydroxide. When the precipitate is formed, it is an endothermic reaction because the change in the product, aluminum hydroxide, decreases in temperature. This is a chemical reaction because different elements rearrange themselves to form a new substance and while they do so, they either absorb heat or give it

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:

A physical change is when you can change it back without a reaction. A chemical change is when you need to make a reaction to separate them. In experiment 1 it was a physical change because the sulfur and iron filings were just a heterogenous mixture. In experiment 2 it was a physical change because when we poured the liquid in the the warm water we just cooled it off into a solid so it didn’t have a chemical change. In experiment 3 it was a chemical change because it had a temperature change and a gas exchange happened. In experiment 4 it was a chemical change because it had temperature change and gas exchange. In experiment 5 it was a chemical change because it formed a precipitate and it changed color to white. In experiment 6 it was physical change because it was salt water which can be

Therefore the more active element takes over, the equation changes, and a reaction takes place. The fourth reaction, zinc and hydrochloric acid, produced a gas, hydrogen gas. The final test was between copper and hydrochloric acid, which resulted in no reaction. Nothing occurred because the hydrogen is more active than the copper, thus the solution does not change. This lab was successful in showing the effect of a chemical reaction and how single replacement reactions

Therefore, a chemical change is taking place because copper is turning into a new metal. Based off of the experiment, it is easy to conclude that vinegar with the combination of air, causes a chemical change on

Every reaction that occurred during this lab was a double replacement reaction, or a chemical reaction in which two aqueous compounds react with each other and result in two different compounds where one is either a solid precipitate, a liquid (water), or a gas. A precipitate in this case is a solid that exits the aqueous solution during the chemical reaction because it is too heavy to stay in the solution. Clear signs of a chemical reaction occurring is the formation of a precipitate, especially in a double replacement reaction, as well as the release of gas bubbles and the product of an acid. During a double replacement, the elements “switch partners” as seen with the base equation for all double replacement reactions, AB+CD→AC+BD. For a lab such as this, a hand lens could be used to confirm the presence of gas bubbles or a precipitate that would not have easily been seen without the device.

Then, grade the graduated cylinder and measure 2.0ml of Potassium Carbonate and pour it into a separate test tube. Record the physical properties of both substances. Clean the station and place all materials back where you found them. Leave the test tube that contains the Copper(II) Sulfate and Potassium Carbonate and come back later and record observations.

Chemical reactions happen in industrial processes, living systems, and chemical laboratories. These reactions are thought to form products during their processes. These reactions are called combustion, synthesis, decomposition, precipitation, single-replacement, double replacement, acid-base, and redox. Combustion is known as burning. It happens when a substance combines with oxygen, which results in the release of large amounts of energy forming heat and light.

In the chemistry world, there are thousands of known chemical reactions that either occur in living systems, in industrial processes, or in chemical laboratories. Few of the types of reactions include Combustion, Synthesis, Decomposition, Precipitation, Single-Replacement, Double-Replacement, Acid/Base, and Redox. It is useful to be familiar with the different types of reactions, because it allows one to know what they are dealing with in a reaction, as well as being able to predict what might happen in additional chemical processes. The first basic type of reaction is Combustion.