Chemistry 3b Summary Questions Flashcards
What is a suitable indicator that can be used in the titrations of sulfuric acid and sodium hydroxide?
1) phenolphthalien
2) methyl orange
An acid and alkali were mixed in a polystyrene cup. They were both at 20C before they were mixed. After they were mixed, the temperature of the solution was 24C. Is the reaction endothermic or exothermic?
Endothermic as energy is being taken in from the surroundings.
Is energy released when bonds or formed or when bonds are broken?
Energy is released when bonds are formed.
Why might the price of bananas increase if we keep burning a lot of fuel?
The more limited crude oil and fossil fuels become, the more expensive they become to use so the vehicles that use them become more expensive too. As bananas are imported, their price will rise as the fuel price rises.
In an exothermic energy level diagram, are the products or reactants at a higher energy?
The reactants are at a higher energy than the products.
What is the activation energy for a reaction?
The minimum amount of energy needed to break the bonds of the reaction.
How does a catalyst affect:
a) activation energy
b) overall energy change for a reaction
a) a catalyst lowers the activation energy for a reaction
b) it doesn’t affect the overall energy change as the energy levels for the reactants and products are the same - they are just reached quicker
What is an advantage of using hydrogen as a fuel in a car engine?
Only forms water so burns cleanly.
What is a disadvantage of using hydrogen as a fuel in a car engine?
1) a special, expensive engine is needed
2) hydrogen is explosive so is hard to store safely
What is a fuel cell?
A fuel cell is an electrical cell that’s supplied with a fuel and oxygen and uses energy from the reaction between them to generate electricity.
Why is the car industry researching fuel cells?
1) could reduce dependency on crude oil
2) burns cleanly so less air pollution in cities
What are two ways of testing for metal ions?
1) flame test - different metal ions give different coloured flames when burnt
2) the colour of the precipitate formed with NaOH - different metal ions give different coloured precipitates
