calorimetry and cooling curves

What is calorimetry

Using a calorimetry to measure change of state and chemical reactions in terms of associated heat transferred

What are the types of thermometers

• liquid-fluid

• Electronic

What does a liquid fluids thermometer have to operate

Either alcohol or mercury , as it will expand and rise to temperature change

What is the liquid filled thermometers main applications

• Use in hospitals and general industries for liquid temp measurements

What does the electric thermistor have to operate

• A thermistor

• Resistance

• Thermocouple

• Infra red waves

What is the main application for a electric thermometer

• can be used in industry for high temperatures

• Used in hospitals

Conduction

The transfer of heat energy in a solid where there exist a difference in temperature

Convection

The transfer of heat by currents in high density regions to low density , resulting in drop in temp

Thermal equilibrium

Point which there is no temp change due to heat energy being used to break molecular forces at phase change

Latent heat

The heat energy taken in or given out when a substance changes state

The greater the molecular forces mean what in terms of temperature

That higher temperature is needed to reduce force of attraction binding the molecule

Chromatography

Method used Ito separate chemical mixtures for analysis

What is the mobile phase

Liquid that transports the substance along the stationary phase

What is the stationary phase

The solid material that absorbs the mixture , (the chromatography paper)

How to calculate the Rf value

Distance travelled by solute / distance travelled by solvent

• you do the dye components divided by the solvent front

TLC compared to paper chromatography

• the stationary phase is a thin layer of unrest I’ve substance like silica on a flat surface like glass

TLC advantages

• mobile phase moves quickly through stationary phase

• They show a greater range of separation of components that paper chromatography

How dependant or results are and how replicable they are is linked to keeping what in constant :

• the solvent

• The amount of stationary phase used

• Teh temperature controls

Gas liquid chromatography steps to working

• liquid sample is injected into the oven

• The oven boils the sample into vapour

• Vapour is carried by inert gas ( helium) through column

• Molecule move through into contact with liquid solvent (helium gas) absorbed onto the solid material

• The tiem taken for sample to pass through machine to detector is the retention time

• The retention time depends on solubility of the sample in the solvents

The applications of gas chromatography

Used t analyse concentration of alcohol in the blood

This is gas chromatography

What is ion exchange chromatography

method For purification of particles and other charged molecules including amino acids

The method of ion exchange

• relies on oppositely charged ions between the mobile phase and stationary phase , typically a low concentration mobile phase interacting with stationary ions weakly thereby ELUTING

What does eluting mean

Extracting one substance from another using a solvent

Cation exchange

• the stationary phase in this type of chromatography is positively charged

• The ionic interaction between positive and negative ions in stationary phase is strong

Anion exchange

• stationary phase is negatively charged

• Positive charged proteins will interact with negative stationary phase molecules and negatively charges molecules will ELUTE from the columns

By lowering the pH in ion exchange chromatography what happens to proton availability and mobile phase

The proton availability increases which makes the mobile phase more positive

What are polar molecules

Molecules without equal distribution of electrons causing opposite electric poles

What’s re non polar molecules

Molecules with equal distribution of electrons resulting to no obsevable poles