[ 557 ] Physical Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Which of the following materials would be a good insulator? A. a tile floor because it transfers heat away from skin B. a steel spoon because it conducts heat from boiling liquids C. a wool blanket because it slows the transfer of heat from skin D. a copper pipe because it accelerates the transfer of heated materials Every chemical reaction needs a certain amount of energy to get started, as illustrated in the graph. Activation energy Heat released Reactants Products Time Energy What type of reaction is shown? A. endothermic, because energy is required after activation to continue the reaction B. exothermic, because additional energy is needed in order to complete the reaction C. exothermic, because the energy level of the products is lower than the energy level of the starting materials D. endothermic, because the energy level of the final materials is higher than that of the starting materials