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, 22.06.2019 22:00
Scientists often have to deal with numbers that are either very large or very small. for example, the radius of the sun is approximately 696,000 kilometers, while bacterial cells are as small as 1.9 × 10-4 millimeters. express each number in an alternate form.
Answers: 1
Chemistry, 23.06.2019 01:00
Reactions in cells take place at about a. 40°c b. 0° c. 100°c d. 60°c
Answers: 1
Chemistry, 23.06.2019 09:30
Which of the following is not a characteristic of a hydrogen bond? 1. it is responsible for the unusual physical properties of water. 2. it is weaker than a covalent bond. 3. it is stronger than other dipole-dipole interactions. 4. it can occur when hydrogen is covalently bound to very electronegative elements liks f, cl, br and i.
Answers: 1
Bound charge does not affect concentration gradients....
Mathematics, 08.11.2019 02:31
Computers and Technology, 08.11.2019 02:31
English, 08.11.2019 02:31
Biology, 08.11.2019 02:31
Mathematics, 08.11.2019 02:31
Mathematics, 08.11.2019 02:31
Social Studies, 08.11.2019 02:31
Spanish, 08.11.2019 02:31