Which of the following is an observation and not an inference? . a.. a cup with steam coming from it will be hot to the touch.. b.. dark clouds in the sky will mean rain later in the afternoon.. c.. bubbles form when two chemicals are mixed together.. d.. a plastic bag moving along the ground is being pushed by the wind.

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.