C6 Flashcards
(37 cards)
What does the pH scale show?
It shows how acidic or alkaline a solution is
- An acid has a pH less than 6
- An alkali has a pH more than 8
- pH 7 is neutral
What do acids produce in water?
They produce hydrogen atoms, H+
When the concentration of H+ ions increases by 10, what happens to the pH level?
Decreases by 1
What makes an acid a ‘strong’ acid?
Strong acids ionise completely in water
What makes an acid a ‘weak’ acid?
Weak acids do not fully ionise in water.
What does an acid and a metal hydroxide form?
Salt + Water
What does an acid and a metal form?
Salt + Hydrogen
What does an acid and a metal carbonate form?
Salt + Water + Carbon Dioxide
How can you make a soluble salt?
Reacting an acid with an alkali.
How can you make an insoluble salt using precipitation?
Reacting 2 soluble salts which produce a precipitate
-e.g. to make lead chloride you mix lead nitrate and sodium chloride which are both soluble
What is the rate of reaction?
How fast the reaction happens
What is the collision theory?
- How often particles collide
- The more frequent the collisions are, the faster the reaction rate is.
- Particles must collide with enough energy for the reaction to take place.
- The more successful collisions, the higher the rate of reaction.
What effect does increasing the temperature have on the rate?
- Particles move faster and have more frequent collisions
- Higher temperatures increase the energy in the reaction, so reactions will be more successful
- Therefore increasing the temperature will increase the rate.
What effect does increasing the concentration/pressure have on the rate?
-There are more particles in the same volume, so collisions are more likely, so the reaction rate increases.
What effect does increasing the surface area have on the rate?
-Particles have more area to react upon (collisions only occur on the surface) so collisions are more likely, so the rate increases.
What effect does a catalyst have upon the rate?
Speeds up reaction by lowering activation energy, but has no effect on the yield
-it is not part of the overall equation
What effect do enzymes have upon the reaction?
If the temperature is too high or low, the enzyme will not work at a high rate-the temperature has to be specific for the enzyme to work at an optimum rate.
What is the equation for rate of reaction?
Amount of product formed / time
What are reversible reactions?
Reactions which can go forwards and backwards
-can reach an equilibrium where the forwards and backward reactions slow down.
What are the 3 factorss which can affect the position of the equilibrium?
- Temperature
- Pressure
- Concentration
How does temperature affect the position of the equilibrium?
If you increase the temperature, the equilibrium will shift towards the endothermic side.
How does the pressure affect the position of the equilibrium?
If you increase the pressure, the equilibrium shifts to the side with fewer particles
How does concentration affect the position of the equilibrium?
If you increase the concentration of the reactants, the equilibrium will shift to the products side.
What is atom economy?
The % of reactants forming desired products.
