When testing for hydrogen gas in the laboratory a glowing splint is inserted into the gas which results in a pop sound. What is associated with the formation of the pop sound? A. physical change
B. chemical change
C. exothermic reaction
D. endothermic reaction

What is the importance of interlocking the fingers and rubbing while washing hands? the palms are the dirtiest parts of the hands. the spaces between the fingers get washed. the backs of the hands get washed. the fingernails are the dirtiest parts of the hands

The equation below shows the reaction of zinc with hydrochloric acid (hcl). zn (s) + 2 hcl (aq) —> zncl2 (aq) + h2 (g) what will happen if the concentration of hcl is decreased? a. more zncl2 will be produced. b. the reaction rate will slow down. c. the hydrochloric acid will become more acidic. d. the reaction will produce water instead of hydrogen gas.

Consider the reaction: 2al(s) + fe2o3(s) → al2o3(s) + 2fe(s) the δhf for fe2o3(s) = -824.3 kj/mole. the δhf for al2o3(s) = -1675.7 kj/mole. finish the equation. δhrxn = [(1)( kj/mole) + (2)( kj/mole)] - [(1)( kj/mole) + (2) ( kj/mole)]