Question
Which of the following phase transitions is/are endothermic? 1. liquid water freezing to a solid at its normal freezing point of 0.0 degree C. 2. the sublimation of solid carbon dioxide into the gas phase. 3. gaseous sulfur dioxide condensing into a liquid at its boiling point of -10.0 degree C a. 1 only b. 2 only c. 3 only d 1 and 2 e 1, 2, and 3 Which equation represents the number of atoms in a body-centered cubic unit cell? a. #atoms = 1 + 1/2 (6) + 1/8 (8) b. #atoms = 1/2 (6) + 1/8 (8) c. #atoms = 1/8 (8) d. #atoms = 1/4 e. #atoms = 1 + 1/8 (8) Which of the following properties of water can be attributed to hydrogen bonding? 1. high melting point 2. high heat of vaporization 3 low vapor pressure
Explanation / Answer
Question 15.
endothermic --> will absorb energy from surroundings
1)
liquid water freezes, so the system releases energy to the surroundings
this is EXOTHERMIC
2)
the sublimation of solid carbon to gas phase
since gas phase contains much larger energy state, there is energy being absorbed
so
this is EXOTHERMIC
3)
gas SO2 donenses... gas to liquid is an energy loss, therefore, this is endothermic as well
choose only 1