Unit 6 ~ Learning Guide Name:

Transcription

1 Unit 6 ~ Learning Guide Name: Instructions: Using a pencil, complete the following notes as you work through the related lessons. Show ALL work as is explained in the lessons. You are required to have this package completed BEFORE you write your unit test. Do your best and ask questions if you don t understand anything! Mixtures and Solutions: 1. In the table below list 3 differences between pure substances and mixtures Pure Substances Mixtures 2. A liquid dissolved in a solid is known as an amalgam while a solid dissolved in another solid is known as what? 3. What are four factors that affect solubility? Molar Concentration: 1. Write the long form and the short form of the concentration formula Page 1 of 11

2 2. If 1.60 mol of table sugar (C 12 H 22 O 11 ) is dissolved to give 750. ml of solution, what is the molar concentration of the solution? 3. A solution of epsom salts may be prepared by dissolving 35.6 g of magnesium sulfate in sufficient water to make ml of solution. Determine the molar concentration of the epsom salts solution. 4. Hydrogen peroxide, H 2 O 2, forms a colorless solution. How many moles of H 2 O 2 are found in 3.50 L of disinfectant solution that has a concentration of M H 2 O 2? 5. What mass of nitre, KNO 3 8H 2 O, is necessary to make 400. ml of a mol/l solution? Page 2 of 11

3 6. Salt of lemon is a dilute solution of potassium bi oxalate (KHC 2 O 4 H 2 O) often used to remove ink stains. What volume of 1.25 M salt of lemon contains 6.00 mol of potassium bi oxalate? 7. Commonly called bleach, sodium hypochlorite (NaOCl) has many uses as a strong base and cleaner. What volume (in ml) of 1.70 M NaOCl can be prepared from 54.7 g of solute? Polarity in Molecules: 1. What is the definition of electronegativity? 2. Why is CCl 4 not a polar molecule? 3. Fill in the following table. It is vital that you have this information memorized for your test! Solute dissolves in Solvent Non-polar dissolves in Polar dissolves in Ionic dissolves in Page 3 of 11

4 Dissociation and Ionic Equations: 1. Why do covalent (molecular) dissolve but not dissociate? 2. For each of the following write i) a balanced chemical formula equation, ii) a total ionic equation and iii) a net ionic equation. Remember if you are given the name of an ionic compound you must balance the formula correctly! a) Magnesium metal is placed in a solution of hydrochloric acid and reacts to form a magnesium chloride solution and hydrogen gas b) Zinc metal is placed in a silver nitrate solution and reacts to form silver metal and a zinc nitrate solution. c) Barium chloride solution is added to lead(ii) nitrate solution in a double replacement reaction. One lead containing precipitate forms while the other product remains in solution. Page 4 of 11

5 d) Sulfurous acid is added to sodium hydroxide. No precipitate forms from this neutralization reaction. e) Aqueous chlorine is added to a solution of aluminum bromide in a single replacement reaction which forms no precipitate and bromine liquid. 3. What is the concentration of each ion in a 5.50 M solution of aluminum sulfate? Write a dissociation equation and put the correct concentration below each ion. Page 5 of 11

6 4. What is the concentration of each ion formed when 94.5g of nickel (III) sulphate is dissolved into ml of water? You will first need to calculate the concentration of the chemical then write a dissociation equation and put the correct concentration below each ion. 5. A g sample of sodium hydroxide and 1.62 g of stromtium hydroxide are dissolved in 100.mL of solution. Assuming that no reaction occurs, calculate the concentration of each ion in the solution. Page 6 of 11

7 Electrolytes: 1. Why are covalent solutions unable to conduct electricity? 2. Name 3 common non-electrolytes 3. Fill in the following table Ion Charge Ion Name Positive Negative 4. Why does not much current flow through a weak electrolyte solution? 5. How can you create an electrolyte other than dissolving a compound? Page 7 of 11

8 Chemical Reactions and Solutions: 1. Use the reaction below to answer the following questions. Remember that M = mol/l 2 CaO (aq) + 4 C (s) 2 CaC 2(s) + O 2(g) a) What volume in ml of 5.00 M calcium oxide is required to completely react with 10.0g of carbon? b) Determine the number of litres of oxygen gas that can be created at STP when 300. ml of 2.50 M calcium oxide reacts completely. c) What volume in ml of 4.75M calcium oxide is required to create 15.3g of calcium carbide? d) What mass of carbon is needed to completely react with 375 ml of 1.65 M calcium oxide? Page 8 of 11

9 2. What is the molar concentration of each ion if 153.7g of tantalum phosphate are dissolved in 350. ml of solution? 3. What is the concentration of each ion in solution when 97.7 grams of Be 3 P 2 and 121 grams of (NH 4 ) 3 P are dissolved to make 500. ml of solution? Page 9 of 11

10 4. What is the molar concentration of each ion when 250. ml of M NH 4 F (aq) are added to 750. ml of M (NH 4 ) 2 CrO 4 (aq)? Answers: Molar Concentration Hints: and = Molar Concentration Answers: M M MgSO mol H 2 O g nitre L ml Page 10 of 11

11 Dissociation and Ionic Equations Hints: 4. and 5. You need to convert grams to mols and then convert mols to M for each ion. One of the ions you will have two M values so you'll need to add those together Dissociation and Ionic Equations Answers: M Al 3+ (aq ) and 16.5 M SO 4 2- ( aq ) M Ni 3+ (aq) and M SO 4 2- (aq) M Na + (aq), M Sr 2+ (aq) and M OH - (aq) Chemical Reactions and Solutions Hints: 1. a) = b) c) = d) You need to convert grams to mols for each compound. Then convert mols to M. 4. The first step is to use the dilution formula to calculate the new concentrations of each compound. Chemical Reactions and Solutions Answers: 1. a) 83.3 ml CaO b) 8.4 L O 2 c) 50.3 ml CaO d) 14.9 g C M Ta 5+ (aq) and 2.16 M PO 4 3- (aq) M Be 2+ (aq), 8.52 M NH 4 + (aq) and 7.24 M P 3- (aq) M NH 4 + (aq), M F - (aq), and M CrO 4 2- (aq) Page 11 of 11