Answer all of the following questions.

Question

1.) Use the equation of sodium chloride dissolving in water to complete the activity.

NaCl(s) ⇄ Na+(aq) + Cl–(aq)

A student is testing two clear liquids. One liquid is water that has been modified to have a basic pH. The other liquid is a sports drink that contains added electrolytes, including Na+(aq). How can the student use the equilibrium reaction of sodium chloride to determine which liquid is which? In three to five sentences, explain your answer. Review the information in Lesson 6. Use the information to answer the question.

2.) Chromate ions react according to the following equation, where the left side of the reaction is yellow and the right side is orange.

CrO42– + 2H+ ⇄ Cr2O72– + H2O

A student adds sodium hydroxide (NaOH) to the solution at equilibrium. In one to two sentences, describe and explain any changes to the solution that the student will observe. Lesson 3 Pages 2-4

3.) In one to two sentences, explain why metal is often used for making wire and the properties that make metal useful. Lesson 7 Page 2

Answer 1

1.) The student can use the equilibrium reaction of sodium chloride to determine which liquid is which by observing how the NaCl(s) dissociates in each liquid. If the sodium chloride completely dissolves and forms Na+(aq) and Cl-(aq) ions, then the liquid is water with a basic pH. If the sodium chloride dissociates but there are additional Na+(aq) ions present, then the liquid is the sports drink containing added electrolytes.

2.) When the student adds sodium hydroxide to the solution at equilibrium, they will observe a color change from the yellow of chromate ions to the orange of dichromate ions. This change occurs because the addition of sodium hydroxide shifts the equilibrium towards the formation of dichromate ions.

3.) Metal is often used for making wire because of its properties such as high electrical conductivity, flexibility, and strength. These properties allow metal wire to efficiently conduct electricity over long distances without breaking or losing too much energy.