Propane (C3 H8 (g), Delta. Hf = –103.8 kJ/mol) reacts with oxygen to produce carbon dioxide (CO2 , Delta. Hf = –393.5 kJ/mol ) and water (H2 O, Delta. Hf = –241.82 kJ/mol) according to the equation below. Upper C subscript 3 upper H subscript 8 (g) plus 5 upper O subscript 2 (g) right arrow 3 upper C upper O subscript 2 (g) plus 4 upper H subscript 2 upper O (g). What is the enthalpy of combustion (per mole) of C3 H8 (g)? Use Delta H r x n equals the sum of delta H f of all the products minus the sum of delta H f of all the reactants.. –2,044.0 kJ/mol –531.5 kJ/mol 531.5 kJ/mol 2,044.0 kJ/mol

How does a scientist the government? a. the scientist tells people in society what to do. b. the scientist determines the policies that the government spends money on. c. the scientist provides unbiased information to the government. d. the scientist makes laws based on his or her research results.

Match the following vocabulary terms to their definitions. 1. amount of energy required to change 1 gram of material from the solid to the liquid state at its melting point 2. a measure of the kinetic energy of the particles of a substance 3. the amount of heat energy required to raise the temperature of 1 gram of liquid water from 14.5°c to 15.5°c 4. amount of energy required to change 1 gram of material from the liquid to the gaseous state at its boiling point 5. the amount of energy required to change 1 gram of a substance 1°c a. temperature b. latent heat of vaporization c. latent heat of fusion d. calorie e. specific heat

3. how much energy in joules is required to evaporate .0005 kg of liquid ammonia to vapor at the same temperature? 4. how much energy ( in megajoules ) is given up by .75 kg of water at 0c when it freezes to form ice at 0c? 5. explain how heat works between and at critical temperatures?