🔥 HEAT FLOW PRINCIPLES & CALORIMETRY

SYSTEM

Specific portion of universe under study; reaction/substance of interest

SURROUNDINGS

Everything exchanging energy with the system; container, air, bath, environment

POSITIVE q

Heat flows INTO system; endothermic; temperature rises

NEGATIVE q

Heat flows OUT OF system; exothermic; temperature drops

SPECIFIC HEAT CAPACITY (c)

Heat required to raise 1 g substance by 1°C; units J/g·°C; formula q = mcΔT

MOLAR HEAT CAPACITY (Cp)

Heat required to raise 1 mole substance by 1°C; units J/mol·°C; formula q = nCpΔT; constant-pressure value noted as Cp

ΔT

Temperature change; T_final − T_initial; determines sign of heat flow

CALORIMETRY

Measurement of heat flow during reactions, phase changes, physical changes; applies conservation of energy in insulated system

CALORIMETER

Insulated device measuring heat transfer; heat lost = heat gained

COFFEE-CUP CALORIMETER

Constant-pressure calorimeter; Styrofoam insulation; uses water temperature change; q_reaction = −q_water; q_water = m_water × 4.184 J/g·°C × ΔT

BOMB CALORIMETER

Constant-volume calorimeter; heavy steel vessel; for combustion/gas reactions; includes water + calorimeter constant; q_reaction = −(q_cal + q_water)

CALORIMETER CONSTANT (C_cal)

Heat capacity of apparatus; J/°C; determined via calibration with known heat input