Corrections Flashcards
Name 2 industries that use enzymes in its production process
brewing
baking
What is a catalyst (3)
- increases rate of reaction
- not used up during the reaction
- lowers activation energy
formula for rate of reaction using formation of a product
= amount of product formed (or lost) / time
Why does a cross disappear in a reaction (2)
Because solid — is precipitated. The solid blocks view of the cross.
name an advantage of a inverted measuring cylinder over a gas syringe
none of the gas escapes before the syringe is connected
What is activation energy
Minimum amount of energy required for a reaction to take place
How does a larger surface area increase rate of reaction
more particles are able to be involved in collisions
How do you find rate of reaction at a specific point in a rate of reaction graph
draw a tangent and find the gradient
what happens to rate of reaction over time (2)
the rate decreases over time due to reactant particles being used up so there are fewer reactant particles
What is sulfur scrubbing (3)
- exhaust gases containing sulfur dioxide are sprayed with ‘limestone slurry’.
- The sulfur dioxide reacts with the slurry to form calcium sulfate
- which is removed as solid waste
benefits of sulfur scrubbing (2)
- reduces sulfur dioxide emissions reducing acid rain
- solid calcium sulfate can be made into plaster boards
composition of modern atmosphere (4)
- 78% nitrogen
- 21% oxygen
- 0.9% argon
- 0.04% CO2
Where did ammonia from our previous atmosphere go
reacted with oxygen to form nitrogen gas and water.
use of nitrogen
unreactive atmospheres for food packaging
describe a test for the gas produced when carbonates decompose (2)
- heat in a boiling tube with delivery tube
- bubble gas through limewater and limewater turns milky
how are gases separated using fractional distillation (2)
- they have different boiling points
- gases collected at different places on the column in order of boiling points
why didn’t scientists believe Alfred Wegener
he was unable to explain how continents moved
2 pieces of evidence Alfred Wegener had of continental drift
- similar fossil patterns on different continents
- coastlines of continents fit together like a jigsaw
What do all metal oxides look like
white solids
ionic formulae for displacement reaction between sodium bromide + chlorine
2Br + Cl2 —- 2Cl + Br2
why does mass decrease in a reaction
gas is released
why are catalysts important in industrial processes
Reactions can take place at lower temperatures so less energy is needed therefore its cheaper to make the products
common name for sodium carbonate
washing soda
what does washing soda do
reacts with calcium and magnesium ions to produce insoluble salts
What does boiling do
decoposes hydrogencarbonate ions
how are oxygen and carbon dioxide levels in the atmosphere maintained
- photosynthesis uses CO2 and releases O2
- respiration uses O2 and releases CO2
- balance is maintained when both oxygen and carbon dioxide are used up at the same rate they are produced
safety measure in reaction of potassium with water
Use a small piece of potassium
what is a practical problem when trying to get crystals to form at 4 degrees celsius and solution to this
- it is lower than room temperature
- difficult to get crystals to form
- place the boiling tube in ice
formula for decomposition of calcium hydrogen carbonate
calcium hydrogencarbonate + water + carbon dioxide
what does adding washing soda to hard water form visibly
a white precipitate
metal properties given in table with melting point, boiling point, density and conductivity (4)
- high boiling point
- high melting point
- high density
- being a conductor
Describe the theory of plate tectonics
- The Earth’s crust is divided into tectonic plates
- these move very slowly
- due to convection currents in the mantle
what ions do group 1 elements form when they react
+1
what ions do group 7 elements form when they react
-1
describe a method of testing for water hardness (4)
- add soap solution to each sample and shake
- the one that produces a lather is soft water
- boil the remaining samples
- the one that lathers after boiling is temporary hard water and the one that does not is permanent hard water
empirical formula =
mass\Ar. NOT Mr
