C4h4 (g) + 2 h2 (g) --> c4h8 (g) combustion reactions involve reacting a substance with oxygen. when compounds containing carbon and hydrogen are combusted, carbon dioxide and water are the products. using the enthalpies of combustion for c4h4 (-2341 kj/mol), c4h8 (-2755 kj/'mol), and h2 (-286 kj/mol), calculate the change in heat for this reaction.

Which statement describes the appearance of a temperature-vs.-time graph? a horizontal line shows that the temperature increases at a constant rate over time. a vertical line shows that the temperature decreases at a constant rate over time. horizontal lines where the temperature is constant during phase changes connect upward-sloping lines where the temperature increases. horizontal lines where the temperature increases are connected by upward-sloping lines where the temperature is constant for each phase.

Which of the following two events occur to create a sea breeze? select all that apply. warm air rises on the ocean and moves toward the land to cool warm air rises on land and moves toward the ocean to cool cool air moves from the ocean to be warmed by the land cool air moves from the land to be warmed by the ocean

What is the main purpose of patent attorneys? defend the company against legal claims manage financial investments invent new products protect rights to new products and processes