Name: ___________________________________ Date: ______________ Practice Test #3 ____ 1. When a precipitation reaction occurs, the ions that do not form the precipitate A) evaporate B) are cations only C) form a second insoluble compound in the solution D) are left dissolved in the solution E) none of these 2. An aqueous solution of potassium chloride is mixed with an aqueous solution of sodium nitrate. The complete ionic equation contains which of the following species (when balanced in standard form)? A) B) C) D) E) ____ 3.
Lesson written by Carolina Sylvestri Experiment: Reaction Between Ions in Aqueous Solutions The Monster Mash Background: Ionic solids dissolve in water to form aqueous solutions which conduct electricity. These solutions contain both positive and negative ions in such numbers that their net electric charge is zero. In this experiment, you will mix various ionic solutions, two at a time, to determine which combinations form precipitates. Knowing which ions are present makes it possible to deduce which of the possible ion combinations are responsible for the precipitates. From your data table, it will then be possible to generate a solubility table.
To find out N2 you have to determine the mass of water produced in the reaction. This mass is the difference between the mass of initial compound (BaCl2•XH2O) and the mass of anhydrous salt (BaCl2). N2 is the ratio of the mass of the water produced in the reaction to the molar mass of
Objectives: The purpose of this lab is to observe the reaction of crystal violet and sodium hydroxide by looking at the relationship between concentration and time elapsed of the crystal violet. CV+ + OH- CVOH To quantitatively observe this reaction of crystal violet, the rate law is used. The rate law tells us that the rate is equal to a rate constant (k) multiplied by the concentration of crystal violet to the power of its reaction order ([CV+]p) and the concentration of hydroxide to the power of its reaction order ([OH-]q). Rate = k[CV+]p[OH-]q To fully understand the rate law, concentrations of the substances must be looked at first. The concentration is measured in molarity.
Introduction: You are aware that sugar dissolves in water but oil does not. What factors determine whether one substance will dissolve in another? A solvent is a substance that is capable of dissolving other substances and forming a homogeneous mixture called a solution. The substance dissolved is called the solute and is the component present in the smallest amount. The dissolving process involves a consideration of the relative strength of three intermolecular attractive forces.
(d) What evidence suggests that nitrate compounds are soluble in water? (e) Write the chemical formula for each precipitate that formed. Apply and Extend (f) Write a balanced chemical equation for each precipitation reaction that occurred. (g) Why is it necessary to use distilled water to prepare the solutions used in this investigation? (h) "Hard" water contains a high concentration of calcium ions.
D) the absence of charged molecules inside cells. Answer: C Page Ref: Section 3 11) The ________ pressure is the pressure required to prevent the flow of solvent through a solvent-permeable membrane that separates two solutions of different solute concentration. A) hydrostatic B) electromotive Answer: C Page Ref: Section 3 12 C) osmotic D) partial 12) Which is true about the solubility of electrolytes in water? A) They are all insoluble in water. B) They are usually only sparingly soluble in water.
The concentration of a solution is the amount of solute that is dissolved into each unit of solvent. In this lab, water (H2O) will be the solvent and sugar/sucrose (C12H22O11). When the density of the solute is greater than the density of the solvent, the density is directly proportional to the concentration of the solute. The relative density of the solute to the solvent can be observed by placing some solute into the solvent without mixing. If the solute floats, then the density of the solvent is greater than the density of the solute.
Computer Additivity of Heats of Reaction: Hess’s Law 18 (1) Solid sodium hydroxide dissolves in water to form an aqueous solution of ions. (2) Solid sodium hydroxide reacts with aqueous hydrochloric acid to form water and an aqueous solution of sodium chloride. NaOH(s) + H+(aq) ) + Cl–(aq) → H2O(l) + Na+(aq) + Cl–(aq) ∆H2 = ? OBJECTIVES • • • • In this experiment, you will Combine equations for two reactions to obtain the equation for a third reaction. Use a calorimeter to measure the temperature change in each of three reactions.
For reaction (II) Pb (NO3)2 + 2KI -> PbI2+2KNO3 Lead nitrate is soluble, so it gets written as ions. The same goes for potassium iodide and potassium nitrate. Complete Ionic equation: 2 K+1 + I-1 + Pb2+ + NO32- -> PbI2 + 2K+1 + NO3-1 Net Ionic Equation: Pb+2 + 2 I-1 -> PbI2 Warm-Up Exercise 2 In this lab you will mix 25 mL of 0.05M lead nitrate with 1.4 mL of 0.025M sodium carbonate. After the reaction occurs, you will filter the solution to remove the precipitate. You will then test the remaining solution for excess lead ion and for excess carbonate ion… Imagine that you mix the two volumes and then freeze frame the reaction so the it does not proceed: 1.