Amole of x reacts at a constant pressure of 43.0 atm via the reaction x(g)+4y(g)→2z(g), δh∘=−75.0 kj before the reaction, the volume of the gaseous mixture was 5.00 l. after the reaction, the volume was 2.00 l. calculate the value of the total energy change, δe, in kilojoules.

Which element would mostly likely have an electron affinity measuring closest to zero

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 statement is true about this reaction? 14n+1h 15o it is a practical source of energy on earth. it occurs only outside the solar system. its product is heavier than each of its reactants. it shows the critical mass of an element.