PLEASE HELP QUICKLY!! Version A
During a lab experiment, Helvetica created 0.436 g of hydrogen gas by reacting 15.00 g zinc
metal with an unlimited amount of hydrochloric acid:
Zn + 2HCI → ZnCl2 + H2
Mr. Poindexter indicated that in order to receive a passing grade for this lab, students must
produce enough hydrogen gas that falls greater than or equal to a 97 percent yield.
What is the theoretical yield based off the information given?
What was the percent yield that Helvetica achieved?
Did Helvetica receive a passing grade on this lab?
Show all work to receive full credit.

Can someone me with questions 12 and 13 plz.

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.)

Astudent conducts an experiment to determine how the amount of water given to a plant affects its growth. what is the independent variable for this experiment?