A chemist is about to perform a titration by adding a base to an acid. What is the most important reason for using a base
instead of water to rinse out the burette?
to make sure the burette is not blocked
to prevent any bacteria from growing in the burette
to make sure the base will flow quickly though the burette
to prevent dilution of the base, which may affect the results
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Ineed ! it’s science and it’s due tomorrow!

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.)

Need ! asap will mark 10 pts using the room temperature line (orange line) and your periodic table, make lists that identify the state of matter (gas, liquid, or solid) in which each element you plotted exists at room temperature. explain your answers