Consider the chemical equations shown here. 2 equations. 1: 2 upper H subscript 2 (g) plus upper O subscript 2 (g) right arrow 2 upper H subscript 2 upper O (g). Delta H 1 equals negative 483. 6 kilojoules divided by 2 equals negative 241. 8 kilojoules per mole. 2: 3 upper O subscript 2 (g) right arrow 2 upper O subscript 3 (g). Delta H 2 equals 284. 6 kilojoules divided by 2 equals 142. 3 kilojoules per mole. What is the overall enthalpy of reaction for the equation shown below? 3 upper H subscript 2 (g) plus upper O subscript 3 (g) right arrow 3 upper H subscript 2 upper O (g). KJ.

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

Suppose a lab group reports a ppercent yield of sand of 105. is it really possible to collect more sand than was originally represented? what is the possible explanation for the extra product?

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.