1. According to the information in the table above, a 1.00g sample of which of the following contains the greatest mass of oxygen?
2.Which of the following could be the identity of a white crystalline solid that exhibits the following properties?
•It melts at 320℃
•It does not conduct electricity as a solid.
•It conducts electricity in an aqueous solution.
3. Which of the following correctly identifies which has the higher first-ionization energy,
Cl or Ar and supplies the best justification?
(A)Cl, because of its higher electronegativity
(B)Cl, because of its higher electron affinity
(C)Ar, because of its completely filled valence shell
(D)Ar, because of its higher effective nuclear charge
1. A student is given the task of determining the I- content of tablets that contain potassium iodide, KI and an inert, water-soluble sugar as a filler. A tablet is dissolved in 50.0ml of distilled water, and an excess ofis added to the solution. A yellow precipitate forms, which is then filtered, washed, and dried. The data from the experiment are shown in the table above.
(a) For the chemical reaction that occurs when the precipitate forms,
(i) write a balanced, net-ionic equation for the reaction, and
(ii) explain why the reaction is best represented by a net-ionic equation.
(b) Explain the purpose of drying and weighing the filter paper with the precipitate three times.
(c) In the filtrate solution, is [K+]greater than, less than, or equal to? Justify your answer.
(d) Calculate the number of moles of precipitate that is produced in the experiment.
(e) Calculate the mass percent of I- in the tablet.
(f) In another trial, the student dissolves a tablet in 55.0ml of water instead of 50.0ml of water. Predict whether the experimentally determined mass percent of iodide, I minusiodide, I minus iodide, I minus will be greater than, less than, or equal to the amount calculated in part (e). Justify your answer.