1. which of the following is a physical change? a. breaking chemical bonds but not changing phase b. a change in phase but no change in molecular structure c. creating a new substance d: enters transfer and change in color 2. which of the following is an example of a chemical change a. mixing of paint colors b. formation of clouds c. metal corrading in salt water d, sugar dissolving in water

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-

Sugar is dissolved in water. which is the solute? sugar neither both water

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.)