In which part of the digestive system does a chemical change of the food first occur?

When the volume and number of particles of a gas are constant which of the following is also constant

Match the acid base pairs by arranging the acid name with the conjugate base formula. hydrogen carbonate hydrogen phosphate carbonic acid read water sulfuric acid phosphoric acid a. co32- b. hso4- c. hco3- d. po43- e. h2po4- f. oh-

0.09 moles of sodium sulfate in 12 ml of solution