An unknown substance undergoes a chemical change that gives off heat. Which statement is true? The types of molecules of the substance before and after the chemical change are different, and the change was endothermic. The types of molecules of the substance before and after the chemical change are the same, and the change was exothermic. The types of molecules of the substance before and after the chemical change are the same, and the change was endothermic. The types of molecules of the substance before and after the chemical change are different, and the change was exothermic.
Answers: 1
Chemistry, 22.06.2019 05:50, carog24
Astudent made a graph plotting the progress of a reaction over time. the student forgot to label the y-axis of the graph. a graph is shown with two graph lines. one graph line starts at a higher position on the y axis and slopes downwards towards the right. the other graph line starts at a lower position on the y axis and slopes upwards towards the right. the two graph lines stop short of intersecting each other and continue as separate lines which gradually become straight and parallel to the x axis. a vertical line is shown at a point where the two graph lines finally became parallel to the x axis. this vertical line is labeled equilibrium. the title on the x axis is time and an arrow pointing towards the right is shown above time. the title on the y axis is left blank. what best explains the label that the student should use on the y-axis? amount, because as the amount of product decreases, the amount of reactant increases over time. reaction rate, because forward and backward reaction become equal at equilibrium. amount, because the amounts of reactants and products become constant after equilibrium is reached. reaction rate, as the rate of forward reaction increases and rate of backward reaction decreases over time.
Answers: 3
Chemistry, 22.06.2019 23:00, genyjoannerubiera
In the reaction h2co3 (aq) + 3nh3 (aq) = 2 nh4+ (aq) + co3 2-, how many electrons are transferred?
Answers: 3
An unknown substance undergoes a chemical change that gives off heat. Which statement is true? The t...
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