Thermodynamics

Calcium carbide (CaC2) reacts with water to form acetylene (C2H2), a gas used as a fuel in welding: CaC2 + 2H2O ==> C2H2 + Ca(OH)2 ^H = 128.0 kJ How many kilograms of CaC2 are consumed in a raction that releases 3.64 x 104 kJ of heat under these conditions? A. 1.82 x 10 to the power of 4 kg B. 284 jg C. -18.2 kg D. 2.33 x 10 to the power of 3 kg E. 18.2 kg

Gas Volume

If a 10.0 g sample of Zn (s) is treated with excess HCl, what volume of hydrogen gas is evolved at STP? Zn + 2HCl --> ZnCl2 + H2 A. 7.36 L B. 6.85 L C. 347 L D. 146 L E. 3.43 L

Specific Heat

A 15.) g block of aluminum at an initial temperature of 27 C absorbs 0.678 kJ of heat. What is the final temperature of the block? The specific heat of Al is 0.902 J g-1C-1. A. 50.1 C B. 38.6 C C 54.5 C D. 68.6 C E. 77.6 C

Torr

While at high altitude, a pilot fills a flexible 2-liter container with air at a pressure of 500 torr. He closes the container and brings it to a location near sea level where the pressure is 750 torr. What is the volume of the container near sea level at the same temperature? A. 2 1/3 liters B. 3/2 liters C. 2/3 liters D. 1 1/3 liters E. 3 liters

Combustion

What volume of O2 (g), measured at 22 C and 763 torr, is consumed in the combustion of 7.50 L of C2H6 (g), measured at STP? A. 28.3 L O2 B. 2.15 x 10 to the fourth power L O2 C. 26.3 L O2 D. 2.11 L O2 E. 8.07 L O2