Chemistry Lab

d) Ethanol, an alternative source of energy, being used to power cars is a chemical change due to the fact that it combusts in the car's engine with oxygen and produces carbon dioxide and water. The ethanol reacts with oxygen and produces two new substances. The products are different from the reactants proving there was a chemical change.

6-3: This process is used by cells to manufacture _biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products__

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

Purpose: The purpose of this experiment is to observe chemical changes in common consumer products to determine if the chemicals are basic, acidic, or remain neutral when mixed with other chemicals.

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.

3> Mixtures can be separated into these components by using physical methods like, decantation, distillation, evaporation, crystallization, sublimation, and filtration.

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.

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

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.

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.

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.

Changes in matter occur every day. There are two types of ways matter can be altered; physically and chemically. Physical changes do not change the composition of the matter while chemical changes occur when one or more substances turn into a completely new substance.

Students in Mrs. Holley’s fourth block chemistry class performed five mini activities including burning a candle, magnesium and paper; combining KI, water, and Pb(NO₃)₂; Magnesium and HCI; and putting paper clips in a jar of water. This was done in order to recognize and distinguish between chemical and physical properties, to recognize and distinguish between chemical and physical changes, and to classify matter.