C3 - Chemical Economics Flashcards
What is an exothermic reaction?
When energy is given out to the surroundings, which is shown by a rise in temperature
What is an endothermic reaction?
This is where it takes in energy from the surroundings and shown by a fall in temperature
In terms of bonds what happens in an exothermic reaction?
A strong bond is formed
In terms of bonds what happens in an endothermic reaction?
Bonds are broken
What is specific heat capacity?
This is the energy needed to make an object of 1kg increase by the temperature of 1 degree
What is the equation for energy transferred?
Energy transferred = mass of water x SHC of water x temperature change
What is the equation for energy given out?
Energy given out = energy released / mass of fuel burned
Summarise the colorimetric method.
1) Measure 200g of water into a copper calorimeter
2) Take the initial temperature of the water then light the wick under it
3) Let the temperature rise to around 20-30 degrees
4) Reweigh the burner to see how much he fuel was used
Name four ways you could increase the rate of reaction
1) Increase the temperature
2) Increase the concentration
3) Increase the surface area
4) Add a catalyst
How do you find the relative atomic mass (A(r))?
Add the two biggest numbers on of the elements
How do you find the relative formula mass (M(r))?
All of the relative atomic masses added together
What are the three main steps in calculating the masses in reactions?
1) Write out the balanced equation
2) Work out the M(r) of the two bits you want
3) Divide to get 1 and then multiply to get all
What is atom economy?
The percentage of reactants changed into useful products
What is the equation of atom economy?
Atom economy = total M(r) of desired products / total M(r) of all products (x100)
Give four examples of why there is always less than 100%?
1) Evaporation
2) Filtration
3) Transferring liquids
4) Not all reactant into product
