What is the relationship between ozone and earth's atmosphere? explain how various substances used by humans have contributed to the depletion of the ozone layer.

Select the correct answer. which statement is true about a polarized object? o a. it gains electrons and becomes negatively charged. ob. it gains protons and becomes positively charged. oc. the number of positive and negative charges can be the same. od. it has to be a metal. o e. there is no change in the distribution of the charge in the object. reset next what

Which is a chemical property of iron? a. it forms iron oxide (rust) when exposed to moisture and air. b. it is a gray–black metal that is hard to the touch. c. it has a melting point of 2795°f (1536°c). d. it is a good conductor of heat

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.)