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Blow the Top Off Chemical Reactions!. Chemical and Physical Reactions. Physical Reaction– a reaction that alters the form or appearance of a material but does not make the material into another substance: change shape, phase change.
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Chemical and Physical Reactions • Physical Reaction– a reaction that alters the form or appearance of a material but does not make the material into another substance: change shape, phase change • Chemical Reaction– a reaction that produces new substances that are made of the same elements, but have changed into different combinations of elements
Observing Chemical Reactions • Chemical changes occur when bonds break and new bonds form – changes in properties and changes in energy that can be observed • Some factors that show a chemical reaction is taking place: • Change in energy • Color change • Formation of a gas • Change in odor • Formation of a precipitate (solid forms from a solution)
Rates of Chemical Reactions • Reaction Rate = time it takes for a chemical reaction to take place. • Chemical reactions do not all occur at the same rate. Examples: explosions, rust
Factors that affect Reaction Rates Temperature – adding heat increases rate, removing heat decreases 2. Agitation – adding movement energy can increase the rate of the reaction.
Factors • Concentration – increasing the amount of a material supplies more particles to react. 4. Surface Area – increase the surface area to exposes more of the particles of the substance, this increases a chemical reaction, decrease the surface area to decrease a chemical reaction
Factors 5. Catalysts – a material that increases the rate of a reaction by lowering the energy needed for the reaction. (Enzymes) 6. Inhibitors – a material used to decrease the rate of a reaction (Preservatives)
Brainstorm! • Using what you have learned about reaction rates, in your groups try to devise 3 different ways to conduct the experiment that will change the rate of the reaction. • Your only materials are the tablet, the water and the film canister.
Procedure • On your lab sheet record the three types of trials you will conduct • Conduct each experiment timing the reaction from the time you combine the materials to the time the top pops off. • Record your results in the data table and complete the conclusion questions with your team.
