When working with repelling magnets, potential energy can be stored when the
magnets are:
pulled apart (moved with the magnetic force)
pushed together (against the magnetic force)

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.

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.)

Write the chemical formula for a compound that is made of an element from group 1 and an element from group 17