Answers: 2
Chemistry, 22.06.2019 11:40
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, 23.06.2019 00:00
Before it was launched, a helium-filled balloon had a pressure of 201 kpa at a temperature of 27°c. at an altitude of 15,000 m, the pressure had decreased to 2.5 kpa and the temperature had dropped to -14 °c. the volume of the balloon increased to 59.3 m3. what is the original volume of the balloon? 13 m3 0.85 m3 0.077 m3 1.17 m3
Answers: 3
Chemistry, 23.06.2019 16:00
Afuel has 30.43% nitrogen and 69.57% oxygen. find the molecular formula of the compound if it has a mass of 92 grams per mole a.no b.n2o4 c.no2 d.n4o8
Answers: 1
Chemistry, 23.06.2019 18:50
Which of the following elements is most likely to have an oxidation state of +2? a. oxygen (0) b. sodium (na) c. chlorine (ci) d. strontium (si)
Answers: 1
The simple substances of matter are called:
molecules
elements
compounds...
molecules
elements
compounds...
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