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PHYSICAL PROCESS q EQUATIONS DECISION MAP. PHYSICAL PROCESS HEAT EXCHANGE (q) CALCULATION. Q = m Hf . Hf = HEAT OF FUSION TABLE B. RECOGNIZE HINTS A ∆T. 2 TEMPERATURES GIVEN ONE TEMP GIVEN AND ONE ASKED FOR. HEATING COOLING HEAT EVOLVED HEAT ABSORBED
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PHYSICAL PROCESS q EQUATIONS DECISION MAP PHYSICAL PROCESS HEAT EXCHANGE (q) CALCULATION Q = mHf. Hf = HEAT OF FUSION TABLE B • RECOGNIZE HINTS • A ∆T. • 2 TEMPERATURES GIVEN • ONE TEMP GIVEN AND ONE ASKED FOR. • HEATING • COOLING • HEAT EVOLVED • HEAT ABSORBED • HOW MANY J OR kJ need to cause a certain ∆T. NO IS THERE A PHASE CHANGE ? • RECOGNIZE HINTS • NO ∆T. • FREEZING • MELTING • SOLID TO LIQUID, LIQUID TO SOLID • AT 0.0 C (WATER) • CONSTANT TEMP • AT FREEZING YES YES Use Q = mC∆T. ∆T = T2 – T1 IS THE SAMPLE AT THE FREEZING POINT NO
RECOGNIZE HINTS • NO ∆T. • CONDENSATION • EVAPORATION • LIQUID TO GAS, GAS TO LIQUID • AT 100 C (WATER) • CONSTANT TEMP • AT BOILING POINT Q = mHV HV = HEAT OF VAPORIZATION TABLE B