How does the size of reactant particles affect combustion?
Smaller reactant particles have a larger surface area, allowing more oxygen to come into contact with the fuel, increasing the rate of combustion.
Why is kindling used to start a fire?
Kindling consists of small pieces of wood with a larger surface area, allowing it to ignite quickly and transfer heat to larger logs.
How does particle size affect cooking time?
Smaller food pieces cook faster because they have a larger surface area, allowing heat to penetrate more quickly.
Why do diced vegetables cook faster than whole vegetables?
Diced vegetables have more surface area exposed to heat, allowing them to absorb heat more quickly and cook faster.
How does refrigeration slow down food spoilage?
Lower temperatures reduce the kinetic energy of microorganisms, slowing down the metabolic reactions responsible for food spoilage.
Why does food cook faster at higher temperatures?
Higher temperatures increase the kinetic energy of molecules, speeding up the chemical reactions that cook food.
How does increasing concentration affect combustion in engines?
A higher concentration of fuel and oxygen increases the frequency of collisions, leading to faster and more efficient combustion.
Why do industrial chemical reactions use high concentrations of reactants?
Higher concentrations increase collision frequency, leading to a higher reaction rate and faster product formation.
What is the function of a catalytic converter in vehicles?
A catalytic converter speeds up the breakdown of harmful gases like carbon monoxide (CO) and nitrogen oxides (NOₓ) into less harmful substances like CO₂ and N₂.
Which metal is commonly used as a catalyst in catalytic converters?
Platinum.
What role do enzymes play in biological processes?
Enzymes act as biological catalysts, speeding up reactions such as digestion, respiration, and muscle contraction.
How does amylase aid digestion?
Amylase catalyses the breakdown of starch into simpler sugars, aiding digestion.
How does pressure affect reaction rates in gases?
Increasing pressure compresses gas molecules, increasing their collision frequency and reaction rate.
Why does food cook faster in a pressure cooker?
Higher pressure raises the boiling point of water, allowing food to cook at a higher temperature and reducing cooking time.
How does pressure influence the Haber process?
Higher pressure increases the reaction rate between nitrogen and hydrogen, improving ammonia production.
How does pickling preserve food?
Pickling uses high concentrations of acid or salt to slow down bacterial growth and prevent food spoilage.
Why is reaction rate control important in pharmaceutical production?
Controlling reaction rates ensures consistency, quality, and efficiency in drug manufacturing.
How does temperature affect chemical reactions in batteries?
Higher temperatures speed up chemical reactions, increasing battery discharge, while lower temperatures slow down reaction rates.
How does temperature influence the development of photographs?
Higher temperatures increase the reaction rate of the developing chemicals, while lower temperatures slow down the process.
Why is controlling reaction rates important in the food and beverage industry?
Reaction rates affect food processing, preservation, and flavour development, making control essential for product quality.
Explanation Questions
Why does increasing surface area increase the rate of combustion?
A larger surface area allows more oxygen to react with the fuel at once, increasing the rate of combustion.
Why does refrigeration not completely stop food spoilage?
Refrigeration slows down, but does not completely stop, the metabolic activity of microorganisms, allowing slow spoilage over time.
Why do car engines require a specific air-fuel ratio for efficient combustion?
The correct ratio ensures complete combustion, maximising energy release and minimising harmful emissions.
Why are catalysts important in industrial chemical processes?
Catalysts speed up reactions, reducing energy costs and improving efficiency without being consumed.
Why does food cook faster in boiling water than in hot air (oven)?
Water has a higher heat transfer rate than air, allowing heat to reach food more quickly.
Why does increasing temperature not always improve industrial reaction efficiency?
Higher temperatures may lead to unwanted side reactions, increased energy costs, or equipment damage.
Why is enzymatic activity affected by temperature?
High temperatures can denature enzymes, changing their shape and preventing them from functioning.
Why does pressure not significantly affect liquid-phase reactions?
Liquids are nearly incompressible, so increasing pressure does not significantly change the number of collisions.
Why is controlling reaction rates important in battery performance?
A stable reaction rate ensures a consistent power output and prolongs battery life.
Why does food preservation involve controlling reaction rates?
Slowing down microbial and chemical reactions prevents spoilage and extends shelf life.