Can any one me to answers this question i don't get it. in advance.
what is the limiting reactant when 6.8 moles of iron react with 8.9 moles of oxygen gas?
unbalanced equation: fe + o2 _ fe2o3
show, or explain, all of your work along with the final answer.

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.)

Which of these features are formed when hot groundwater is forced out through cracks in the earth's surface?

Δu of , in kj/kg, as it isto k, (a)as a of , (b) at , (c) at .