Factors Affecting Reaction Rates
How can Reaction Rates be affected?
The speed with which a reaction can take place can be influenced by several factors: concentration, surface area, temperature, and the presence of a catalyst. The higher the concentration of reactants, the more molecules there are to interact and thus the there is a higher likelihood of products being formed. Similarly, a higher surface area also increases the chances of these molecules from coming into contact with one another to make products. Raising the temperature increases the kinetic energy of the molecules, thus increasing their chances of overcoming the energy barriers they need to have the reaction go to completion. Catalysts form lower energy intermediates, thus allowing reactants to become products with less energy required.
adapted from:
DiGiuseppe, M., Haberer, S., Salciccioli, K., Sanader, M., & Vavitsas, A. (2012). Nelson Chemistry 12 University preparation. Toronto, ON: Nelson Education Ltd.
The speed with which a reaction can take place can be influenced by several factors: concentration, surface area, temperature, and the presence of a catalyst. The higher the concentration of reactants, the more molecules there are to interact and thus the there is a higher likelihood of products being formed. Similarly, a higher surface area also increases the chances of these molecules from coming into contact with one another to make products. Raising the temperature increases the kinetic energy of the molecules, thus increasing their chances of overcoming the energy barriers they need to have the reaction go to completion. Catalysts form lower energy intermediates, thus allowing reactants to become products with less energy required.
adapted from:
DiGiuseppe, M., Haberer, S., Salciccioli, K., Sanader, M., & Vavitsas, A. (2012). Nelson Chemistry 12 University preparation. Toronto, ON: Nelson Education Ltd.
LESSON OVERVIEW (SPECIFIC EXPECTATIONS: D2.8, D3.5)
Lesson Hook/Minds On:
Give students an entrance slip asking the following questions:
“What dissolves faster in your coffee; a sugar cube or powder sugar? “
“Which is the faster way to get a cake; leaving the mixed batter on the kitchen table or putting it in a hot oven?”
“If your dog does it's business, where will there be a stronger odour; if your dog does it on your carpet or in your backyard?”
Engage students in a brief discussion asking what they thought and how they came to their conclusions.
Give students an entrance slip asking the following questions:
“What dissolves faster in your coffee; a sugar cube or powder sugar? “
“Which is the faster way to get a cake; leaving the mixed batter on the kitchen table or putting it in a hot oven?”
“If your dog does it's business, where will there be a stronger odour; if your dog does it on your carpet or in your backyard?”
Engage students in a brief discussion asking what they thought and how they came to their conclusions.
Teaching Strategy:
Students will conduct a lab activity to explore the different factors affecting reaction rates: concentration, surface area, temperature, and the presence of a catalyst. It will be a 'bell-ringer' lab where students rotate from station to station within an allotted time. The lab outline also includes guiding and follow-up questions that students will work through as they carry out their experiments. |
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Consolidation:
Give each lab group an exit slip that they can work on together. Pose the exact same questions as in the entrance slip, but this time ask for a scientific explanation as to why:“Why does powder sugar dissolve faster in your coffee than a sugar cube? “
“Why will you get a cake faster after you bake the batter as opposed to not baking it?”
“Why is your dog's business going to appear to smell more on your carpet than in your backyard?”
Collect these exit slips to gauge levels of student understanding.
Give each lab group an exit slip that they can work on together. Pose the exact same questions as in the entrance slip, but this time ask for a scientific explanation as to why:“Why does powder sugar dissolve faster in your coffee than a sugar cube? “
“Why will you get a cake faster after you bake the batter as opposed to not baking it?”
“Why is your dog's business going to appear to smell more on your carpet than in your backyard?”
Collect these exit slips to gauge levels of student understanding.
FOPP: Professional practice and commitment to students and student learning
Click below for a few resources that can be used in conjunction with a lesson to further demonstrate the factors affecting reaction rates.