 Moles:  PV/RT=n  Goal for Press=4.57 atm  (4.57atm)(.700L)/( L*atm/mol*K)(273K)=mol HCl  Moles HCL=.143 mol=moles Baking Soda .143mol NaHCO 3 (84.0 grams/mol)= 12.0 grams Baking Soda.  12.0 grams Baking soda= 12.0 mL HCl  Amount of H 2 O 20 mL  NaHCO 3 + HCL = NaCL + H 2 O + CO 2

 Run #1:  Baking Soda: grams  HCl: 12 mL  H2O: 20mL  Distance: 2 feet  Run #2:  Baking Soda: grams  HCl: 12 mL  H2O: 20 mL  Distance: 2 feet  Run #3:  Baking Soda: grams  HCl: 12 mL  H2O: 20 mL  Distance: 6 feet  Run #4:  Baking Soda: grams  HCl: 12 mL  H2O: 20 mL  Distance: 4 feet

 Test runs usually resulted in distances between 5ft. And 20ft.  The car was redesigned to have less weight and fit bottle easier.