{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

mid2a_f04

# mid2a_f04 - Please use the following constants and...

This preview shows pages 1–3. Sign up to view the full content.

Please use the following constants and conversions in the problems below as needed Planck’s constant : h = 6.626 × 10 -34 J-s Speed of Light : c = 3.00 × 10 8 m/s Rydberg Constant : R H = 1.10 × 10 7 m -1 Energy levels in hydrogen atom : E n = (-2.18 × 10 -18 J)(1/n 2 ) 1. [7 points] Which one of the following is an exothermic process? (a) ice melting (b) water evaporating (c) boiling soup (d) condensation of water vapor (e) Ammonium thiocyanate and barium hydroxide are mixed at 25 °C and the temperature drops 2. [7 points] The standard enthalpy of formation for ammonia, NH 3 (g), is H f ° = -46.2 kJ/mol. How much heat is released/absorbed when 1 mole of N 2 (g) is reacted with three moles of H 2 (g) to produce ammonia (at constant pressure)? (a) 46.2 kJ of heat is released (b) 46.2 kJ of heat is absorbed (c) 92.4 kJ of heat is released (d) 92.4 kJ of heat is absorbed (e) 23.1 kJ of heat is released 3. [7 points] Consider the combustion reaction between octane and oxygen in the cylinder of an automobile. The reaction generates CO 2 , H 2 O and heat, and at the same time the expanding gases push up the piston thereby powering the car. If the system is defined as the contents of the cylinder (not including the piston or the cylinder) which of the following statements is true for the system in this process? 4. [7 points] Which one of the following statements is true ?

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}