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 ...continues
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
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
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 ...continues
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
What masss of water in grams, produces 729 J when cooled from 58.0 degrees Celcius to 28.0 degrees Celsius? A. 3.00 B. 0.0412 C. 0.172 D. 24.3 E. 5.81
A balloon is filled with helium. Its volume is 5.90 L at 26 degrees C. What will be its volume at -78 degrees C assuming no pressure change? A. -17.1 L B. 9.04L C. 6.93L D. 17.7 E. 3.85 L
For the following reaction, what is the enthalpy of cyclization per mole of actylene? 3C2H2 (g) --> C6H6 (l) ^H = -630 kJ A. 210 kJ/mol C2H2 B. -630 kJ/mol C2H2 C. 0 kJ/mol C2H2 D. -210 kJ/mol C2H2 E. -1890 kJ/mol C2H2
A balloon of helium whose volume is 2.20 L at 25 degrees C is cooled by pouring liquid N2 over it. The final temperature of the balloon is -196 C. What is the final volume, in L? A. 0.57 B. 8.5 C. -17 D. 0.28 E. 2.2
The minimum energy needed to eject an electron from a sodium atom is 4.41 x 10 to the power of -19J. What is the maximum wavelength of light, in nanometers, that will show a photoelectric effect with sodium?
