Question

1.As a food chemist for a major potato chip company, you are responsible for determining the sodium content of new potato chip products for the packaging label. The potato chips are seasoned with table salt, NaCl. You weigh out a handful of the chips, boil them in water to extract the salt, and filter the boiled chips through a Büchner funnel to remove the soggy chip pieces. You analyze the chip filtrate for Cl– and find that it takes 64.1 mL of 0.350 M AgNO3 to reach the equivalence point of the reaction.
Provide the molecular equation that is valid at the equivalence point of the reaction. Include states of matter.

2.If the sample of chips used to make the filtrate weighed 85.0 g, what mass of sodium is present in one serving (28.0 g) of chips?

Answer 1

AgNO3 (aq)+ NaCl (aq) -----> AgCl (s) + NaNO3 (aq) ( molecular equation)

Ag+ NO3- + Na++ Cl- -----> AgCl + Na + NO3-

Net ionic equarion boils down to

Ag+ +   Cl- ----> AgCl (s)

Moles of AgNO3 = 0.35 x 64.1/1000 =0.022435 moles

Since at equivalence point moles are equal moles of Sodium =0.022435 moles

mass of AgCl = 0.022435 x 143 ( Molecular weight of AgCl) = 3.21 gms

Mass of sodium in 0.022435 moles= 0.022435 x 23= 0.516 gm

3.21 gms of filtrate correspond to 0.516 gms of sodium

85 gms correspond to 85 x 0.516/3.21 =13.66 gms of sodium

Sodium present in 28 gms of chips = 13.66 gms