SCIENCE 9 CONCEPT 4 CHEMICAL REACTIONS

Transcription

1 SCIENCE 9 CONCEPT 4 CHEMICAL REACTIONS

2 VOCABULARY TERMS CONCEPT 4 Chemical reaction Reactants Products Exothermic Endothermic Combustion Corrosion Cellular respiration Conservation of mass Closed systems Catalyst Enzyme

3 Learning Concept Observe and describe patterns of chemical change, by observing heat generated or absorbed in chemical reactions, and identifying examples of exothermic and endothermic reactions

4 Recall a chemical reaction takes place when two or more substances combine to form new substances Materials at the start of the reaction are called reactants Materials produced at the end of the reaction are called products

5 When heat is released/produced in a chemical reaction, it is referred to as exothermic Burning wood Metabolizing food When heat is absorbed, it is referred to as endothermic Chemical cold pack

6 Frozen Flask

7 Learning Concept Observe and describe patterns of chemical change, by identifying factors that affect rates of reaction

8 There are four factors that can affect the rate of a chemical reaction Presence of a catalyst Concentration of reactants Temperature of reactants Surface area of reactants

9 Presence of a catalyst Catalysts are substances that help a reaction proceed faster Not used up (consumed) during the reaction Particular catalysts are called enzymes a type of catalyst found in reactions in living things

10 Concentration of reactants Greater concentration means faster reaction There are more atoms of each reactant available

11 Temperature of reactants More heat added, the faster the reaction occurs Added heat causes the atoms to move faster, increasing the chances they will collide

12 Surface area of reactants Greater surface area means there is more area available for reaction

13 Learning Concept Describe familiar chemical reactions, and represent these reactions by using word equations and chemical formulas and by constructing models of reactants and products Observe and describe evidence of chemical change in reactions between familiar materials, by: Describing combustion, corrosion and other reactions involving oxygen Observing and inferring evidence of chemical reactions between familiar household materials

14 Three types of reactions occur where oxygen is reacting Combustion oxygen reacts with a substance to form a new substance and give off thermal energy Fire A hydrocarbon reacts with oxygen Products are always carbon dioxide and water vapour

15 Science Log A butane lighter is used to light a candle. Butane and oxygen react to form carbon dioxide and water vapour. Write the word equation Write the chemical equation

16 Corrosion oxygen in air reacts with a metal Rust

17 Science Log Mater was left out in Radiator Springs for too long. Because his body was made out of iron, oxygen reacted with it and produced iron oxide. Write the word equation Write the chemical equation

18 Cellular respiration food (glucose) reacts with oxygen to produce energy (ATP) water and carbon dioxide

19 Science Log Green plants containing chlorophyll are one of a very small group of living things that can create their own food they are autotrophs. The process of photosynthesis occurs in the chloroplasts, and involves the reaction of carbon dioxide and water to produce glucose and oxygen gas. Write the word equation Write the chemical equation

20 Law of Conservation of Mass states that the total mass of the products produced in a reaction is the same as the total mass of the reactants Matter is not created nor destroyed in chemical reactions

21 Experiments must be done in a closed system no additional material is allowed to enter or leave An open system is one where additional material can enter or leave