Moles of CO2 evolved .0174 Moles .0192 Moles 10. of your results, what is the ma

ID: 1017714 • Letter: M

Question

Moles of CO2

evolved

.0174

Moles

.0192

Moles

10. of your results, what is the mass of NaHCO3 in an Alka Seltzer tablet? What is the percent mass of NaHCO3 in an Alka Seltzer tablet?

Beaker # Beaker( water,vinegar) Mass (g) Initial Mass (g) Final Mass (g) Mass of CO2 evolved

Moles of CO2

evolved

Moles of NaCO3 consumed Mass of NaHCO3 1 115.000g 118.000g 117.318g .682g .0155 Moles .0155 Moles 1.302g 2 115.005g 118.005g 117.241g .764g

.0174

Moles

.0174 Moles 1.462 g 3 115.011g 118.011g 117.164g .847g

.0192

Moles

.0192 Moles 1.613g 4 115.016g 118.016g 117.133g .883g .0194 Moles .0194 Moles 1.630 g 5 115.021g 118.021g 117.138g .883g .020 Moles .020 Moles 1.680 g 6 115.027g 118.027g 117.143g .884g .020 Moles .020 Moles 1.680 g

Explanation / Answer

10.

Alka Seltzer is an effervescent tablet that contains aspirin, citric acid and sodium bicarbonate. When NaHCO3 dissolved in water following reaction takes place.

NaHCO3(s) Na+(aq) + HCO3-(aq)

Acetic acid, which will donate H+ to water to create H3O+(aq) is then added to the mixture. With the

addition of acetic acid the following acid-base reaction then takes place:

2. HCO3-(aq) + H3O+(aq) 2H2O(l) + CO2 (g)

In Beaker 1.

Mass of NaHCO3 in Alka Seltzer tablet

Mass of CO2 evolved = Initial Mass (g) - Final Mass (g)

118.000g -117.318g = .682g CO2

.682g CO2/1 x 1 mole CO2/ 44.01g x 0.0155 mole NaHCO3/0.0155mole CO2 x 84.01g NaHCO3/1mole NaHCO3

=1.30g NaHCO3

Mass of NaHCO3 in Alka Seltzer tablet is 1.30g

Mass of 1 Alka Seltzer tablet = Initial Mass (g ) - Beaker( water, vinegar) Mass (g)

= 118.000g – 115.000g = 3.000g