To test the effectiveness of a gunpowder mixture, 1 gram was exploded under controlled stp conditions, and the
reaction chamber was found to expand to 310 cm2. what volume would these gases occupy at the temperature
produced by an uncontrolled explosion (2,200°c) and 2.1 atmospheres of pressure?
5,900 cm
1,300 cm
7.7 x 104 cm
1,000 cm

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.)