Whensampleof 100mL of 0.098 M stannousfluorideis mixed with 55mL of 0.10 M Na3PO4 , 1.078 g precipitate of stannousphosphateis obtained. Calculate The theoretical yield andpercent yieldof Sn3(PO4)2.Note: the below equation is not balanced.3SnF2(aq) + 2Na3PO4(aq) = Sn3(PO4)2(s) + 6NaF(aq)

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 completes a titration by adding 12.0 milliliters of naoh(aq) of unknown concentration to 16.0 milliliters of 0.15 m hcl(aq). what is the molar concentration of the naoh(aq)? 1)5.0 m 2)0.20 m 3)0.11 m 4)1.1 m

To calculate percent by mass, use the equation below: calculate the percent by mass of each element. %n = % %h = % %o = %