Determine the concentration of a solution of sodium hydroxide (NaOH) using a 0.500M Potassium Hydrogen Phthalate (KHP) standard solution. Acid-base indicator phenolphthalein is added in its (colorless) acidic form to a precise volume sample of KHP. The base NaOH is slowly added to the same of KHP. Once all the KHP has reacted with the base, the first excess drop of NaOH will cause the indicator to convert to its basic (pink) form.

Starch and are common polysaccharide carbohydrates found in plants. sucrose glycogen fructose cellulose

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins

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.)