calorimetry

What is calorimetry used for?

Used to estimate chemical energy stored in dry biomass

What is the overall method

• burning sample of dry biomass in calorimeter

• Heats a known volume of water

• Change of temperature of water = estimate of chemical energy the sample contains

How do you find dry mass (method)

• weigh initial mass of crucible

• Place sample in crucible

• Set oven to low temp (not high or there is burnt mass)

• Remove + weigh crucible at regular intervals

• Once mass stops decreasing - dehydrated

• End mass - original mass = dry mass

What do you do once you’ve found the dry mass

Pu in calorimeter

Burn dry sample

Uses energy released to heat known of volume of water

Measure change in temp of water = (used to estimate chemical energy stored within sample)

What is the limitation in terms of removing water

It takes a long time to fully dehydrate (it dehydrates at a low temp)

What is a limitation in terms of equipment

Precise equipment is needed (thermometer/mass balance)

What is the limitation in terms of calorimeter

The more basic and simple the calorimeter - less accurate the estimate is for chemical energy stored in plant sample

What is a bomb calorimeter?

Ensures almost all the heat energy from burnin sample is transfreeed to water (highly accurate estimate)