Consider the conversion of a substance from solid to liquid. at one atmosphere pressure and at the normal melting point of the substance, which one of the following terms below equals zero for the system?

∆e
∆h
∆s
∆g

Using data from seismic waves, geologists have learned that earth’s interior is made up of several

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.)

How are isotopes of the same element alike?