chem U3AOS1 p1

specific heat capacity definition and SI unit

Amount of energy needed to raise temp of 1g by 1°C

J/g°C

How to reduce heat loss in calorimetry

Add insulation around setup

Add lid (with hole for thermometer)

Change material of test tube

CF formula

CF=E/delta T

Fossil fuel define

Non renewable resources derived from ancient remains of plants and animals

define renewable resource

• can be replenished faster than it is consumed

• Made from

Tryglyceride components

Glycerol molecule with 3 fatty acids

fatty acid composition

Carboxylic acid with long carbon chains

Condensation reaction

Two molecules combine to form one with the loss of water

bioethanol

ethanol that is made from the anaerobic fermentation of sugar and starch products by yeast

biodiesel

fatty acid methyl esters

fuel that is made from the transesterification of fats and oils in organic matter

carbon neutral

does not result in net production of carbon dioxide from sourcing or consumption

coal

combustible carbonized plant matter (fossil fuel), formed by the partial decay of plant matter

natural gas

coal seam gas sourced from coal deposits (fossil fuel)

fuel

substance that is used, usually combusted, that has energy stored in its bonds

Fossil fuel

a natural fuel such as coal or gas, formed in the earth, in the past, from the remains of living organisms.

non renewable- cannot be produced as quickly as it is consumed

Renewable resource

replenished by natural processes within a relatively short period of time

partially oxidised fuel meaning

higher or lower heat of combustion?

fuel with oxygens already present in molecular formula

lower heat of combustion

cellular respiration equation

C6H12O6(aq) +6O2(g) → 6CO2(g) + 6H2O(l)

biogas

CH4 and CO2, formed through anaerobic breakdown of organic materials by bacteria

bioethanol formation equation

C6H12O6 → 2C2H5OH(aq) + 6CO2(aq)

what is calorimetrry

method used to determine the changes in energy of a system by measuring heat exchanges with surroundings

calorimetry calculation steps

1. find energy (chemical/electrical)

   E=VIt or E = H*n

2. CF = E/t

3. E=CF*t

4. H=q/n

Why do calorimeters need to be calibrated

• imperfect insulation/absorbance of heat

• energy from the reaction is not solely transferred to the water

• heat is absorbed by internal components of calorimeter as well

• calibration means the factors are taken into account

• relationship of temp to heat can more accurately be calculated

• without calibration, the enthalpy value obtained will always be less than the true value for a given calorimeter using a fixed quantity of solution.

features of electrodes which allow fuel cells to function properly

porous to gases

allow conduction of a current

have embedded catalysts

direct contact spontaneous energy transformation

chem → thermal

why?  bc needs and external circuit for electrons to go through

indirect contact spontaneous energy transformation

chem → electrical

Why is molten electrolysis not viable?

• Difficult/dangerous to maintain required temperature

• Lack of proper equipment to safely collect toxic gases

• Difficult to keep reactants from coming into contact (violent spontaneous reactions)

• Issues sourcing suitable electrodes

• Issues maintaining electric ciruit at high temperature

hydrogen fuel cell equations

what is denaturation?

• disruption of bonds within quaternary/tertiary/secondary structure

• shape and structure of the active sites are altered.

• results from high temp or ph

  
  

effect of ph on enzyme activity?

• low ph, high h+ conc

  • results in protonation of acidic and basic groups -COOH and -NH3+

• high ph, low h+ conc

  • results in deprotonation

both extremes result in denaturation

• ionisation of R groups can affect substrate binding as:

  • An altered tertiary structure can change confirmation of the active site.

  • Amino acid residues within the active site may no longer be able to bind to the substrate.