Chemistry, 16.10.2020 16:01, cjjohnson1221
A physical change is easier / more difficult to reverse than a chemical change.
Answers: 2
Chemistry, 22.06.2019 11:40, Wemaybewrong
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.)
Answers: 1
Chemistry, 22.06.2019 15:30, ricardotavarez6
How does a large body of water, such as the ocean, influence climate?
Answers: 1
A physical change is easier / more difficult to reverse than a chemical change....
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