Chemical Changes Essay

A chemical change is caused in the formation of one or more new substances. Key features of knowing that a chemical change has occurred is seeing a change in colour, smelling a gas or seeing bubbles, seeing a new solid (known as precipitate) forming in a clear solution, observing that energy is produced or absorbed in the form of heat or light. An example is when applying Hydrochloric Acid onto Litmus Paper; the paper changes colour. A physical change is different because it occurs when no new

recognize and differentiate between physical and chemical changes in matter. Physical change can be defined as a usually reversible change from one state (solid, liquid, or gas) to another without a change in chemical composition. The physical properties of a substance--such as size, shape, density, or state--are altered. An example of a physical change is ripping paper. A chemical change can be defined as a usually irreversible chemical reaction that results in the formation of one or

order to clearly comprehend whether the solubility is a chemical or physical change, we must under the definition of it in the first place. Solubility means the ability for a substance to actually dissolve or in other terms solute in a solvent. Also, we need to know the difference between a physical or chemical change. In a chemical change, a chemical reaction occurs in which a new type of substance is established. In a physical change, the change itself does not alter what the substance is causing it

Purpose: Can a chemical change be determined? Hypothesis: A chemical change can be determined by one or more of the following, the creation of gas, heat, precipitate or colour change. It cannot be easily inversed. Materials: • Safety goggles • 2 small test tubes • Test-tube rack • 4 labelled medicine droppers • 2 mL distilled water • Indicator solution (phenolphthalein) in a dropper bottle • 2 mL of Solution A (0.5% sodium hydroxide) • 2 mL of Solution B (2.0% sulfuric acid) • 2 mL of Solution

The indicators of the chemicals changes that has happened were, heat was produced (when the blue flame occured because of methane and oxygen gas heated the watch glass) in reaction 1, the bottom of the watch glass became black (changed colour and a precipitate was formed) due to the same procedure but less oxygen for reaction 2, and the colour changed for the foil and bubbles/gases were produced for reaction 3. Moreover, in reaction 4, the colour of the copper also changed and the smell was like

Detecting Signs of Chemical Change REAC 399 Prepared by: Elizabeth G. Perez Date of experiment: October 3, 2006 Course: Chemistry 100/60 Abstract: 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. Introduction: An elements¡¦ reaction to certain substances may be predicted by its

CHM130 Lab 3 Identification of Chemical Change Name: Nolan Strommer A. Data Table (24 points) Place your completed data table here: Reactants Predictions Before Combining Observations After Combinin g Starch + I2 It becomes purple It becomes blue and a little purple. Food coloring + NaOCl The color of the food coloring will disappear. The color of food coloring is on the top of NaOCI, NaOCI is under the food coloring. Food coloring + CH3COOH The color will be the same as the food coloring

***SAFETY PROCEDURE*** WEAR YOUR SAFETY GOGGLES AND APRON. PHYSICAL AND CHEMICAL CHANGES Purpose: 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. Apparatus: Forceps Bunsen burner Funnel Wire gauze Crucible tongs Filter paper Test tubes, large and small Universal clamp Test tube rack Stirring rod Ring stand and ring Materials:

Chemical reactions usually involve the absorption or release of energy, often as heat. When a chemical reaction occurs at constant pressure, the energy released is equal to the heat flow and is known as enthalpy. Heat is a form of energy that flows into or out of a system because of temperature differences. If a reaction releases heat, it is exothermic; if a reaction absorbs heat, it is endothermic. The enthalpy change of a reaction is measured using a calorimeter, an insulated device that prevents

Title: Physical and Chemical Changes Purpose: Recognize and distinguish between chemical and physical changes Apparatus and Material: evaporating dish, Bunsen burner, wood splint, test tubes, micro spatula, dropper, mortar and pestle, test tube holder, safety goggles, lab apron. Piece of paper, NaCl (sodium chloride), water, 6 M HCL (hydrochloric acid), 0.1 M AgNO3 (silver nitrate), Mg ribbon, 6 M HCL (hydrochloric acid), CuSO4 5 H2O, 0.50g iron fillings, 0.50g of powdered sulfur, magnet,