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7.3 Application Rate of Reaction in Daily Life

7.3 Application of Factors that Affect the Rate of Reaction in Daily Life
CHEMISTRY • Form 4 • Chapter 7: Rate of Reaction

7.3Application of Factors that Affect the Rate of Reaction in Daily Life

The factors affecting the rate of reaction—size of reactants (total surface area), concentration, temperature, and catalysts—are widely applied in daily life activities, cooking, medicine, and industrial processes. Understanding these factors enables us to speed up desired reactions or slow down unwanted reactions.

Learning Objectives

  • 7.3.1 Explain with examples the application of factors that affect the rate of reaction in daily life.

Factors Affecting Rate of Reaction in Daily Life and Industry

Four main factors—size, concentration, temperature and catalyst—control how fast reactions happen around us.

1. Size of Reactant

Cutting potatoes into thin strips or chewing antacid tablets increases the total surface area, so reactions happen faster.

2. Concentration

Compressing petrol vapour in a car engine increases the concentration of fuel particles, allowing rapid combustion. High concentrations of sulphur dioxide also speed up acid rain corrosion.

3. Temperature

Frying in hot oil (up to 180 °C) cooks food faster than boiling in water at 100 °C. Low temperatures in refrigerators slow down food decay.

4. Catalyst

Platinum, Pt, in catalytic converters converts harmful exhaust gases into non-harmful products. Yeast enzymes catalyse fermentation at 37 °C.

Catalytic Converter Conversion

Harmful exhaust gases are converted into non-harmful products over a platinum catalyst:

Harmful gases

Unburned hydrocarbons, CxHy
Carbon monoxide, CO
Nitrogen oxides, NOx

Non-harmful products

Water, H2O
Carbon dioxide, CO2
Nitrogen, N2

Brief Explanation

How each factor is applied in daily life and industry.

Controlling the rate of reaction is essential in daily life and industrial manufacturing. By increasing the total surface area of solid reactants, compressing fuel vapour, raising the temperature, or using catalysts, we can speed up desired reactions or slow down unwanted ones.

1. Size Factor — Total Surface Area

  • Action of medicines: Doctors advise patients to chew antacid tablets instead of swallowing them whole. Breaking the tablet into smaller pieces increases the total surface area exposed, increasing the rate of reaction between the medicine and stomach acid.
  • Cooking food: Potatoes are cut into thin slices or long strips so they cook faster because more surface area is exposed to cooking oil.
  • Combustion: Coal burns faster in small chips than in large lumps because small chips provide a larger total surface area exposed to oxygen.

2. Concentration Factor

  • Corrosion due to acid rain: Iron buildings near industrial areas corrode faster because the atmosphere contains a high concentration of acidic pollutants such as sulphur dioxide.
  • Combustion of petrol in car engines: Petrol vapour and air are compressed in the combustion chamber before ignition. Compression increases the concentration of petrol vapour, allowing the petrol to burn very quickly until it explodes. The energy released moves the car.

3. Temperature Factor

  • Cleaning: Washing clothes with detergent powder and hot water combines chemical action and higher temperature to increase the rate of reaction, making cleaning quicker.
  • Cooking food: Food cooks faster at higher temperatures. Water boils at 100 °C, while cooking oil does not boil even at 180 °C. Frying in hot oil cooks food faster than boiling in water. In pressure cookers, high pressure increases the boiling point of water, cooking food faster.
  • Food preservation: In refrigerators, low temperature decreases the rate of chemical reactions and decreases the growth rate of bacteria that cause food decay, maintaining freshness such as the freshness of milk.

4. Catalyst Factor

  • Catalytic converter: Modern cars are fitted with catalytic converters containing a platinum catalyst, Pt, to reduce atmospheric pollution. The converter changes unburned hydrocarbons, CxHy, carbon monoxide, CO, and nitrogen oxides, NOx, into water, H2O, carbon dioxide, CO2, and nitrogen, N2.
  • Making alcohol: Ethanol, C2H5OH, is produced through the fermentation of glucose using enzymes in yeast as a catalyst at an optimum temperature of 37 °C.
Factor Daily life / industrial application Effect on rate of reaction
Size of reactant Chewing antacids, cutting potatoes into strips, burning coal chips Increases total surface area, so reaction is faster
Concentration Compressed petrol vapour in car engines, acid rain corrosion Higher concentration increases reaction rate
Temperature Frying in hot oil, hot water laundry, refrigeration Higher temperature speeds up; lower temperature slows down
Catalyst Platinum in catalytic converters, yeast enzymes in fermentation Provides alternative pathway, speeds up reaction without being consumed
Industrial Application: Haber Process (Synthesis of Ammonia)
Ammonia, NH3, is produced by the direct combination of nitrogen gas, N2, and hydrogen gas, H2. Increasing pressure increases the percentage yield of NH3, while increasing temperature decreases the percentage yield. At 350 °C the yield is higher but the rate of reaction is too slow. At 550 °C the rate is fast but the yield is significantly lower. In industry, an iron catalyst and an optimum compromised temperature of around 450 °C with high pressure are used to overcome this disadvantage.

Try to Answer First

Answer mentally, then check the explanation.

1

Why are patients advised to chew antacid tablets rather than swallow them whole?

Answer: Chewing breaks the tablet into smaller pieces, which increases the total surface area exposed to the stomach acid, thereby increasing the rate of reaction to neutralise stomach acid faster.
2

Name three harmful polluting gases found in car exhaust and their corresponding harmless products after passing through a catalytic converter.

Answer: Harmful gases: unburned hydrocarbons, CxHy; carbon monoxide, CO; and nitrogen oxides, NOx. Harmless products: water, H2O; carbon dioxide, CO2; and nitrogen, N2.
3

Based on Figure 7.19, what happens to the percentage yield of ammonia when the operating temperature is increased from 350 °C to 550 °C?

Answer: The percentage yield of ammonia decreases.

Common Mistakes

Avoid these errors when applying rate of reaction factors.

!
Confusing the effect of temperature on rate versus yield: students often assume a higher temperature gives a higher yield of ammonia in the Haber process. In reality, higher temperature increases the rate of reaction but decreases the percentage yield.
!
Assuming smaller pieces mean smaller surface area. Breaking or cutting a substance into smaller pieces increases the total surface area exposed, not decreases it.
!
Thinking boiling water cooks food faster than frying in oil. Water boils at 100 °C, whereas cooking oil reaches much higher temperatures such as 180 °C without boiling, allowing food to cook faster in oil due to the higher temperature.

Common Misconceptions

Compare each misconception with the correct fact.

Misconception

Catalysts are consumed or used up during the reaction in a catalytic converter.

Correct Fact

Catalysts like platinum, Pt, alter the reaction rate by providing an alternative pathway and remain chemically unchanged at the end of the reaction.

Misconception

Storing food in a refrigerator stops bacterial growth and reactions completely.

Correct Fact

The low temperature only slows down the rate of bacterial growth and decay reactions; it does not stop them entirely.

Summary

Key facts to remember.

  • Size Factor: Cutting food into thin slices or chewing antacid tablets increases the total surface area exposed, increasing the rate of reaction.
  • Concentration Factor: Compressing petrol vapour in car cylinders increases concentration, enabling rapid combustion; higher concentration of sulphur dioxide increases acid rain corrosion.
  • Temperature Factor: Frying in oil up to 180 °C or using hot water for laundry speeds up reactions. Low temperatures in refrigerators slow down decay.
  • Catalyst Factor: Platinum, Pt, in catalytic converters converts CxHy, CO, and NOx into H2O, CO2, and N2. Yeast enzymes catalyse glucose fermentation into ethanol at 37 °C.

Quick Activity

Complete all parts before checking your score.

A. Objective Quiz

1

Which catalyst is used in a car catalytic converter to convert harmful exhaust pollutants into non-harmful gases?

2

Why does food cook faster when fried in cooking oil compared to being boiled in water?

B. Fill in the Blanks

3

Breaking up an antacid tablet into smaller pieces increases the total ________ exposed to stomach acid.

4

Compressing petrol vapour and air in the engine combustion chamber increases the ________ of the fuel mixture, allowing it to burn very quickly.

C. Match the Scenario with the Factor

Drag each scenario on desktop. On mobile, tap a scenario and then tap the matching box.

Scenario

Cutting potatoes into thin strips High levels of sulphur dioxide causing rapid building corrosion Keeping milk in a refrigerator to prevent spoiling Fermentation of glucose using yeast enzymes at 37 °C

Factor Affecting Rate

1Factor: Size of reactant (total surface area)
2Factor: Concentration of reactant
3Factor: Temperature
4Factor: Catalyst
Complete every answer before checking.
 

Keywords

Tap or hover over a term to read its meaning.

Antacid Surface area Catalytic converter Fermentation Acid rain
The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of Pandai.

7.3 Application Rate of Reaction in Daily Life

7.3 Application of Factors that Affect the Rate of Reaction in Daily Life
CHEMISTRY • Form 4 • Chapter 7: Rate of Reaction

7.3Application of Factors that Affect the Rate of Reaction in Daily Life

The factors affecting the rate of reaction—size of reactants (total surface area), concentration, temperature, and catalysts—are widely applied in daily life activities, cooking, medicine, and industrial processes. Understanding these factors enables us to speed up desired reactions or slow down unwanted reactions.

Learning Objectives

  • 7.3.1 Explain with examples the application of factors that affect the rate of reaction in daily life.

Factors Affecting Rate of Reaction in Daily Life and Industry

Four main factors—size, concentration, temperature and catalyst—control how fast reactions happen around us.

1. Size of Reactant

Cutting potatoes into thin strips or chewing antacid tablets increases the total surface area, so reactions happen faster.

2. Concentration

Compressing petrol vapour in a car engine increases the concentration of fuel particles, allowing rapid combustion. High concentrations of sulphur dioxide also speed up acid rain corrosion.

3. Temperature

Frying in hot oil (up to 180 °C) cooks food faster than boiling in water at 100 °C. Low temperatures in refrigerators slow down food decay.

4. Catalyst

Platinum, Pt, in catalytic converters converts harmful exhaust gases into non-harmful products. Yeast enzymes catalyse fermentation at 37 °C.

Catalytic Converter Conversion

Harmful exhaust gases are converted into non-harmful products over a platinum catalyst:

Harmful gases

Unburned hydrocarbons, CxHy
Carbon monoxide, CO
Nitrogen oxides, NOx

Non-harmful products

Water, H2O
Carbon dioxide, CO2
Nitrogen, N2

Brief Explanation

How each factor is applied in daily life and industry.

Controlling the rate of reaction is essential in daily life and industrial manufacturing. By increasing the total surface area of solid reactants, compressing fuel vapour, raising the temperature, or using catalysts, we can speed up desired reactions or slow down unwanted ones.

1. Size Factor — Total Surface Area

  • Action of medicines: Doctors advise patients to chew antacid tablets instead of swallowing them whole. Breaking the tablet into smaller pieces increases the total surface area exposed, increasing the rate of reaction between the medicine and stomach acid.
  • Cooking food: Potatoes are cut into thin slices or long strips so they cook faster because more surface area is exposed to cooking oil.
  • Combustion: Coal burns faster in small chips than in large lumps because small chips provide a larger total surface area exposed to oxygen.

2. Concentration Factor

  • Corrosion due to acid rain: Iron buildings near industrial areas corrode faster because the atmosphere contains a high concentration of acidic pollutants such as sulphur dioxide.
  • Combustion of petrol in car engines: Petrol vapour and air are compressed in the combustion chamber before ignition. Compression increases the concentration of petrol vapour, allowing the petrol to burn very quickly until it explodes. The energy released moves the car.

3. Temperature Factor

  • Cleaning: Washing clothes with detergent powder and hot water combines chemical action and higher temperature to increase the rate of reaction, making cleaning quicker.
  • Cooking food: Food cooks faster at higher temperatures. Water boils at 100 °C, while cooking oil does not boil even at 180 °C. Frying in hot oil cooks food faster than boiling in water. In pressure cookers, high pressure increases the boiling point of water, cooking food faster.
  • Food preservation: In refrigerators, low temperature decreases the rate of chemical reactions and decreases the growth rate of bacteria that cause food decay, maintaining freshness such as the freshness of milk.

4. Catalyst Factor

  • Catalytic converter: Modern cars are fitted with catalytic converters containing a platinum catalyst, Pt, to reduce atmospheric pollution. The converter changes unburned hydrocarbons, CxHy, carbon monoxide, CO, and nitrogen oxides, NOx, into water, H2O, carbon dioxide, CO2, and nitrogen, N2.
  • Making alcohol: Ethanol, C2H5OH, is produced through the fermentation of glucose using enzymes in yeast as a catalyst at an optimum temperature of 37 °C.
Factor Daily life / industrial application Effect on rate of reaction
Size of reactant Chewing antacids, cutting potatoes into strips, burning coal chips Increases total surface area, so reaction is faster
Concentration Compressed petrol vapour in car engines, acid rain corrosion Higher concentration increases reaction rate
Temperature Frying in hot oil, hot water laundry, refrigeration Higher temperature speeds up; lower temperature slows down
Catalyst Platinum in catalytic converters, yeast enzymes in fermentation Provides alternative pathway, speeds up reaction without being consumed
Industrial Application: Haber Process (Synthesis of Ammonia)
Ammonia, NH3, is produced by the direct combination of nitrogen gas, N2, and hydrogen gas, H2. Increasing pressure increases the percentage yield of NH3, while increasing temperature decreases the percentage yield. At 350 °C the yield is higher but the rate of reaction is too slow. At 550 °C the rate is fast but the yield is significantly lower. In industry, an iron catalyst and an optimum compromised temperature of around 450 °C with high pressure are used to overcome this disadvantage.

Try to Answer First

Answer mentally, then check the explanation.

1

Why are patients advised to chew antacid tablets rather than swallow them whole?

Answer: Chewing breaks the tablet into smaller pieces, which increases the total surface area exposed to the stomach acid, thereby increasing the rate of reaction to neutralise stomach acid faster.
2

Name three harmful polluting gases found in car exhaust and their corresponding harmless products after passing through a catalytic converter.

Answer: Harmful gases: unburned hydrocarbons, CxHy; carbon monoxide, CO; and nitrogen oxides, NOx. Harmless products: water, H2O; carbon dioxide, CO2; and nitrogen, N2.
3

Based on Figure 7.19, what happens to the percentage yield of ammonia when the operating temperature is increased from 350 °C to 550 °C?

Answer: The percentage yield of ammonia decreases.

Common Mistakes

Avoid these errors when applying rate of reaction factors.

!
Confusing the effect of temperature on rate versus yield: students often assume a higher temperature gives a higher yield of ammonia in the Haber process. In reality, higher temperature increases the rate of reaction but decreases the percentage yield.
!
Assuming smaller pieces mean smaller surface area. Breaking or cutting a substance into smaller pieces increases the total surface area exposed, not decreases it.
!
Thinking boiling water cooks food faster than frying in oil. Water boils at 100 °C, whereas cooking oil reaches much higher temperatures such as 180 °C without boiling, allowing food to cook faster in oil due to the higher temperature.

Common Misconceptions

Compare each misconception with the correct fact.

Misconception

Catalysts are consumed or used up during the reaction in a catalytic converter.

Correct Fact

Catalysts like platinum, Pt, alter the reaction rate by providing an alternative pathway and remain chemically unchanged at the end of the reaction.

Misconception

Storing food in a refrigerator stops bacterial growth and reactions completely.

Correct Fact

The low temperature only slows down the rate of bacterial growth and decay reactions; it does not stop them entirely.

Summary

Key facts to remember.

  • Size Factor: Cutting food into thin slices or chewing antacid tablets increases the total surface area exposed, increasing the rate of reaction.
  • Concentration Factor: Compressing petrol vapour in car cylinders increases concentration, enabling rapid combustion; higher concentration of sulphur dioxide increases acid rain corrosion.
  • Temperature Factor: Frying in oil up to 180 °C or using hot water for laundry speeds up reactions. Low temperatures in refrigerators slow down decay.
  • Catalyst Factor: Platinum, Pt, in catalytic converters converts CxHy, CO, and NOx into H2O, CO2, and N2. Yeast enzymes catalyse glucose fermentation into ethanol at 37 °C.

Quick Activity

Complete all parts before checking your score.

A. Objective Quiz

1

Which catalyst is used in a car catalytic converter to convert harmful exhaust pollutants into non-harmful gases?

2

Why does food cook faster when fried in cooking oil compared to being boiled in water?

B. Fill in the Blanks

3

Breaking up an antacid tablet into smaller pieces increases the total ________ exposed to stomach acid.

4

Compressing petrol vapour and air in the engine combustion chamber increases the ________ of the fuel mixture, allowing it to burn very quickly.

C. Match the Scenario with the Factor

Drag each scenario on desktop. On mobile, tap a scenario and then tap the matching box.

Scenario

Cutting potatoes into thin strips High levels of sulphur dioxide causing rapid building corrosion Keeping milk in a refrigerator to prevent spoiling Fermentation of glucose using yeast enzymes at 37 °C

Factor Affecting Rate

1Factor: Size of reactant (total surface area)
2Factor: Concentration of reactant
3Factor: Temperature
4Factor: Catalyst
Complete every answer before checking.
 

Keywords

Tap or hover over a term to read its meaning.

Antacid Surface area Catalytic converter Fermentation Acid rain
The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of Pandai.
Chapter : Rate of Reaction
Topic : Application of Factors that Affect the Rate of Reaction in Daily Life
Form 4 Chemistry
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