1. Review chemical vs. physical reactions 2. Chemical reactions video 3. Useful chemical reactions research assignment

Transcription

1 Science 24: Day Review chemical vs. physical reactions 2. Chemical reactions video 3. Useful chemical reactions research assignment

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3 Which reaction was your favorite? What kinds of things did you observe? What did all the chemical reactions have in common?

4 Baking a cake Processing films Dying hair Driving a car Fruit ripening Rust Batteries Teeth whiteners Marked out of 5: Pick one of the chemical reactions on the left (or come up with your own). 1) Research how the chemical reaction works. 2) Either type or write a paragraph to explain how it works IN DETAIL! Include any important chemical names AND how the reaction occurs. 3) Present your research to the class (explain what you found out!) 5 a thorough and accurate explanation was provided 4 the explanation was mostly accurate and thorough 3 the explanation was somewhat accurate and thorough 2 the explanation was severely lacking either in accuracy or thoroughness 1 the explanation was severely lacking in accuracy and explanation 0 no explanation of the chemical reaction was provided

5 Science 24: Feb 18th 1. Review useful chemical reactions 2. Vinegar and baking soda demo 3. Notes on chemical reactions 4. Assignments

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7 2.2: Changes That Occur Chemical reaction: substances you start with are not the same as the substances you end with Indicators of chemical change: gases may be given off or new solids formed colors may change odours may be given off

8 Introduction to Word Equations Word equations are representations of a chemical reaction. Reactants > Products If there is more than one reactant, they are separated with a plus sign. If there is more than one product, they are separated with a plus sign. The reactants and products are separated with an arrow. Reactant 1 + Reactant 2 > Product 1 + Product 2 Vinegar and baking soda example:

9 In the vinegar, baking soda, and candle demonstration, we saw 2 types of chemical reactions: 1) Combustion: a fuel burns in oxygen ex. 2) Neutralization: an acid is added to a base to produce water and a salt ex.

10 Science 24: Feb 19th 1. Finish lesson on word equations 2. Word equations and combustion/ neutralization worksheets 3. Lesson on evidence of chemical change and energy of chemical changes 3. Demo 4. Assignments

11 Identify if the following is neutralization or combustion reaction: 1) magnesium hydroxide + hydrochloric acid > magnesium chloride + water 2) methane + oxygen > carbon dioxide + water + heat 3) butane + oxygen > carbon dioxide + water + heat 4) calcium hydroxide + hydrobromic acid > calcium bromide + water

12 How do we write word equations from sentences? ex. Sodium bicarbonate and acetic acid reacted to produce carbon dioxide, water, sodium ions, and acetate ions

13 Assignment: 1) Word equation sheet 2) Combustion or neutralization sheet

14 2.3 Evidence That Change Has Occurred 1) Different colour produced 2) Odour produced 3) Bubbles appear 4) Precipitate (solid formed during chemical reaction) 5) Energy is given off or taken in

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16 Science 24: Feb 20th 1. Mind maps on reactions 2. Lesson on energy of chemical changes 3. Demo 4. Assignments

17 Make a Mind Map of the following words: Chemical change Physical change Neutralization Combustion Word Equation

18 Science 24 Chapter 2 Notes.notebook February 20, Energy and Chemical Reactions Energy Change obvious or unnoticeable production or absorption of a form of energy as part of chemical reaction Examples: Is it absorption or production of energy? 1) Fireworks 2) Rusting 3) Gasoline 4) Baking bread

19 Exothermic processes making ice cubes formation of snow in clouds condensation of rain from water vapor a candle flame Endothermic processes melting ice cubes conversion of frost to water vapor evaporation of water mixing sodium sulfite and bleachbaking bread rusting iron burning sugar forming ion pairs combining atoms to make a gas molecule mixing strong acids and water nuclear fission forming a cation from an atom in the gas phase cooking an egg producing sugar by photosynthesis separating ion pairs splitting a gas molecule apart mixing water and ammonium nitrate melting solid salts

20 Reactions in chemistry are described as endothermic and exothermic, not as absorption or production of heat. Endothermic reaction: A reaction that absorbs energy. Ex) photosynthesis carbon dioxide + water + energy > glucose + oxygen Exothermic reaction: A reaction that produces energy. Ex) metabolism fats + carbohydrates > heat + energy

21 Assignments: 1) Questions p. 37 #1 3 2) Endothermic and Exothermic Reactions Sheet

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