Which statement about the atomic nucleus is correct? a. The nucleus is made of protons and neutrons and has a negative charge. b. The nucleus is made of protons and neutrons and has a positive charge. c. The nucleus is made of electrons and has a positive charge. d. The nucleus is made of electrons and has a negative charge. Please select the best answer from the choices provided A B C D

How do you identify the anode on a power source such as a battery? how do you identify the cathode? how are terms anion and cation?

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.)

#7 how does the structure of amino acids allow them to form a polypeptide? each amino acid has an amino group and a carboxyl group. each amino acid has a hydrogen atom and a carboxyl group. each amino acid has a carboxyl group and an r group. each amino acid has an r group and a hydrogen atom.