Answers: 3
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 15:00
The coriolis effect influences neither wind speed nor wind direction wind speed both wind speed and wind direction wind direction
Answers: 1
Chemistry, 23.06.2019 16:00
Henry moseley used x-ray experiments to determine the atomic number of elements. how did his discovery contribute to the development of the periodic table? a.it confirmed that elements should be arranged in strict order of increasing atomic mass. b.it led to elements with similar atomic numbers being grouped together. c.it allowed the elements to be placed in strict order of increasing atomic number. d.it showed that the way mendeleev grouped elements together was completely wrong.
Answers: 1
Chemistry, 23.06.2019 17:20
What is the relationship between ka and kb with kw? the sum of ka and kb equals the auto-dissociation constant for water. the product of ka and kb equals the auto-dissociation constant for water. the quotient of ka and kb equals the auto-dissociation constant for water. the difference of ka and kb equals the auto-dissociation constant for water.
Answers: 3
20.5L of a gas 195K and 1.25 atm will have what volume at 2.70 atm and 295k...
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