Question 1 of 11 The graph shows the change in temperature of a sample of water in a closed system as thermal energy is added over time. 150°C 100°C TELE Temperature (°C) 50°C 0°C -50°C 10 20 30 40 Time (min) 50 60 What happens in the water during changes of state? A. Its particles move at a lower speed B. Its particles maintain a constant speed. c. Its temperature varies constantly D. Its temperature increases slowly

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)