Which of the following best describes an atom?A)Protons and electrons grouped together in a random pattern. B) A core of electrons and neutrons surrounded by protons. C) A core of protons and neutrons surrounded by electrons. D) I’m not sure. I need more help with this topic.

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.)

Calculate the number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.

Why are people not able to skip a dive to the deepest part of the ocean