[Part 3]- C8- the rate and extent of chemical change 💥 Flashcards
Justify the use of catalysts, in household and industrial products
Hint: effective catalysts for…
- although industrial catalysts [such as gold or platinum] are typically very expensive, they are the most effective catalysts for particular reactions
Justify the use of catalysts, in household and industrial products
Hint: extra energy needed
- moreover, although some catalysts may be very expensive, they’re cheaper than paying the extra energy needed, without a catalyst.
- This is because, a higher temperature and pressure would be needed to have the same rate of reaction [without using a catalyst]
How can catalysts help the environment ?
Hint: operating at…
- catalysts, help the environment- as operating at lower temperatures and pressures, conserves fossil fuels [a non-renewable resource]
How do catalysts combat climate change ?
- ; operating at high temperatures and pressures, usually involves the use of fossil fuels.
- therefore, catalysts combat climate change= conserving fossil fuels, doesn’t release carbon dioxide into the atmosphere.
How are catalysts cost effective, for industrial purposes ?
- catalysts remain chemically unchanged at the end of the reaction [not used up]- meaning, they be be reused again and again.
- meaning a tiny amount of a catalyst can be used, multiple times- making it more cost effective, for industrial purposes.
What’s a disadvantage of catalysts ?
Hint: impurities in the reaction mixture
- catalysts in chemical plants, can eventually become ‘poisoned’- meaning they don’t work anymore.
- This is because, impurities in the reaction mixture combine with the catalyst, and stop it from working properly.
What is a reversible reaction ?
- a reversible reaction, is a reaction in which the products of the reaction, can react to produce the the original reactants.
- ⇌ [this is the symbol, for a reversible reaction]
How can we change the direction of reversible reactions ?
Hint: conditions
- we can change the direction of reversible reactions, by changing the conditions.
In reversible reactions, what is the reaction to the right known as ?
- in reversible reactions, the reaction to the right is known as the forward reaction
In reversible reactions, what is the reaction to the left known as ?
- in reversible reactions, the reaction to the left is known as the backwards reaction
What side are the products and reactants, in reversible reactions?
- in reversible reactions, the reactants are still on the left side, and the products are still on the right side.
- [ ; if the reaction is written in reverse, the same rule applies.]
What are the key rules of energy, in reversible reactions ?
- if a reversible reaction is exothermic in one direction, the reversible reaction is then endothermic in the opposite direction.
- ; the same amount of energy, is also transferred [in each case]
What are two example, of a reversible reaction ? [2]
Hint: ammonium chloride
- an example of a reversible reaction, is:
- heating the compound: ammonium chloride
- and, heating hydrated copper sulfate
What’s a word equation, for the reversible reaction of heating the compound: ammonium chloride ?
Hint: hydrogen
- ammonium chloride ⇌ ammonia + hydrogen chloride
How can heating the compound: ammonium chloride, be a reversible reaction ?
- when we heat the compound, it reacts to form ammonia and hydrogen chloride
- ; if we take the product and cool them down, they can then react together to reform the compound: ammonium chloride.
How can we change the direction, in the reversible reaction: ammonium chloride ?
Hint: cooling
- by heating it, we can make the reversible reaction go forwards [and form ammonia and hydrogen chloride]
- ; by cooling the reversible reaction, we can make it go backwards [and reform ammonium chloride]
What’s a word equation, for the reversible reaction of heating hydrated copper sulfate ?
- hydrated copper sulfate ⇌ anhydrous copper sulfate + water
How can heating hydrated copper sulfate, be a reversible reaction ?
- if hydrated copper sulfate [which is blue] is heated, it reacts to form: anhydrous copper sulfate [which is white] ; it also produces water.
- but if we add water to grab anhydrous copper sulfate, the reaction reverses to hydrated copper sulfate
RECAP: What are endothermic reactions ?
- an exothermic reaction, is a reaction that transfers energy from the reacting molecules to the surroundings [usually by heating].
- so the temperature of the surroundings increases.
- think exit= exothermic reaction- heat is given out
RECAP: What are exothermic reactions ?
- endothermic reactions are a reaction that take in energy, from their surroundings.
- in endothermic reactions, the temperatures of the surroundings decreases [gets colder]
- think in= endothermic reaction- energy is taken in.
What is equilibrium ?
- [chemical] equilibrium, is a state in a reaction where the rate of the forward reaction, is equal to the rate of the reverse reaction.
- Fill in the gaps: In dynamic equilibrium, the ____________ of the reactants and products remain constant over time, even though the ________ is still ongoing.
- In dynamic equilibrium, the concentration of the reactants and products remain constant over time, even though the reaction is still ongoing.
