H2o has a mc021-1.jpghvap = 40.7 kj/mol. what is the quantity of heat that is released when 27.9 g of h2o condenses?

4. absorption has the highest risk of overdose due to increased potency. a. rectal b. oral c. transdermal d. intranasal

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.)

Which change to the system wood cause the freely-moving piston to lower?