Please Help. Urgent. For each chemical equation below, write the number of product molecules that will form from the reaction. Then, circle the limiting reactant. (Note: The coefficients in front of the reactants indicate the number of reactant molecules or atoms present.)

5C + 6O2 ___CO2

4Na + 8Cl2 ___NaCl

3CO2 + 4H2O ___H2CO3

7N2 + 9H2 NH3

10Zn + 16HCl ___ZnCl2 +___H2

Joe shines white light into a bowl half full of water at an angle of incident of 27.5°. calculate the angle of refraction in the water given the indices of refraction for air and water are 1.00 and 1.36, respectively.

Which metal exist in liquid state and can be cut with knife ?

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.)