{"id":3358,"date":"2023-10-05T07:58:36","date_gmt":"2023-10-05T07:58:36","guid":{"rendered":"http:\/\/localhost\/ecole9ja\/?p=3358"},"modified":"2023-10-05T08:03:51","modified_gmt":"2023-10-05T08:03:51","slug":"week-4-ss2-third-term-chemistry-notes","status":"publish","type":"post","link":"https:\/\/ecolebooks.com\/nigeria\/posts\/week-4-ss2-third-term-chemistry-notes\/","title":{"rendered":"Week 4 &#8211; SS2 Third Term Chemistry Notes"},"content":{"rendered":"<p>\u00a0<strong>WEEK FOUR<br \/>\n<\/strong><strong>TOPIC: ACID\/BASE REACTIONS<br \/>\n<\/strong><strong>CONTENT<br \/>\n<\/strong><\/p>\n<ul>\n<li>Preparation of Standard Solutions.\n<\/li>\n<li>Indicators\n<\/li>\n<li>\n<div>Calculations based on Acid-Base Titration.\n<\/div>\n<p>\u00a0<\/li>\n<\/ul>\n<p><strong>TITRATION<br \/>\n<\/strong>There are two types of quantitative analysis namely: volumetric and gravimetric analysis.  Volumetric analysis is based on volume measurement while gravimetric analysis involves direct mass measurement.<\/p>\n<p>\u00a0Volumetric analysis is carried art using Titration.  In titration, a standard solution (one of known concentration must be using be used to react with a solution of unknown of concentration)<\/p>\n<p>\u00a0<strong>PREPARATION OF A STANDARD SOLUTION<br \/>\n<\/strong>A standard solution is a solution of which the concentration is known .A standard solution is prepared by weighing a pure solute, for instance, and dissolving it in a suitable solvent, usually water, and making up the solution to a definite volume in a volumetric flask.<\/p>\n<p>\u00a0For instance, a solution known to contain exactly 10.6g of anhydrous sodium trioxocarbonate (IV), Na<sub>2<\/sub>CO<sub>3<\/sub>, in 1 dm3 of solution is a standard solution.<br \/>\n<strong>Preparation of 0.1mol\/dm<sup>3<\/sup>NaOH<br \/>\n<\/strong>         40g NaOH dissolved in 1 dm<sup>3<\/sup> of the water gives 1.0mol\/dm<sup>3<\/sup> solution<br \/>\n\u00a0\u00a0\u00a0\u00a0XgNaOH will be dissolved in 1 dm3 of water to give 0.1mol\/dm<sup>3<\/sup><br \/>\n\t\u00a0\u00a0\u00a0\u00a0Xg = 40g x 0.1mol\/dm<sup>3<\/sup><br \/>\n\t\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a01.0mol\/dm<sup>3<br \/>\n<\/sup>= 4g<\/p>\n<p>\u00a0Therefore, 4g of sodium hydroxide pellet is measured, dissolved in water and made up to 1dm<sup>3 <\/sup>mark to obtain 0.1mol\/dm<sup>3<\/sup>NaOH<\/p>\n<p>\u00a0<strong>Preparation of 0.1mol\/dm<sup>3<\/sup>HCl<br \/>\n<\/strong>To prepare 0.1mol\/dm<sup>3<\/sup>HCl, the dilution formula is used to determine the volume of the stock acid that will be measured and dissolved in water to obtain the desired concentration.<br \/>\nThe dilution formula is C<sub>1<\/sub>V<sub>1<\/sub> = C<sub>2<\/sub>V<sub>2<\/sub><br \/>\n\tWhere C<sub>1<\/sub> = concentration of stock acid = 11.6mol\/dm<sup>3<\/sup> (for HCl)<br \/>\n\u00a0\u00a0\u00a0\u00a0V<sub>1<\/sub> = volume of stock acid\u00a0\u00a0\u00a0\u00a0<br \/>\n\u00a0\u00a0\u00a0\u00a0C<sub>2<\/sub> = desired concentration of acid = 0.1mol\/dm<sup>3<\/sup><br \/>\n\t\u00a0\u00a0\u00a0\u00a0V<sub>2<\/sub> = volume of water = 1000cm<sup>3 <\/sup>(1dm<sup>3<\/sup>)<br \/>\n<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0758_Week4SS2Th1.png\" alt=\"\"\/>\u00a0\u00a0\u00a0\u00a0V<sub>1<\/sub> = C<sub>2<\/sub>V<sub>2\u00a0\u00a0\u00a0\u00a0<\/sub>= 0.1 x 1000 = 8.6cm<sup>3<\/sup><br \/>\n\t\u00a0\u00a0\u00a0\u00a0         C<sub>1\u00a0\u00a0\u00a0\u00a0<\/sub>      11.6<br \/>\nThus, 8.6cm<sup>3<\/sup> of the stock acid is measured using a measuring cylinder and added to water, then made up to 1dm<sup>3<\/sup> to obtained 0.1 mol\/dm<sup>3<\/sup>HCl.<\/p>\n<p>\u00a0<strong>EVALUATION<\/strong><\/p>\n<ol>\n<li>Describe how to prepare 0.05mol\/dm<sup>3<\/sup> H<sub>2<\/sub>SO<sub>4<\/sub>\n\t\t<\/li>\n<li>List the apparatuses used during volumetric analysis(titration)\n<\/li>\n<\/ol>\n<p>\u00a0<strong>INDICATORS FOR ACID\/BASE TITRATION<br \/>\n<\/strong>Acid-base indicators are dyes that change colour when according to the pH of the medium. The table below shows some titration and their suitable indicator:<\/p>\n<p>\u00a0<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0758_Week4SS2Th2.png\" alt=\"\"\/><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0758_Week4SS2Th3.png\" alt=\"\"\/><strong>Acid \/ base\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Indicator<br \/>\n<\/strong>Strong acid and strong base\u00a0\u00a0\u00a0\u00a0methyl orange or phenolphthalein<br \/>\nStrong acid and weak base\u00a0\u00a0\u00a0\u00a0methyl orange<br \/>\nWeak acid and strong base\u00a0\u00a0\u00a0\u00a0phenolphthalein<br \/>\nWeak acid and weak base\u00a0\u00a0\u00a0\u00a0No suitable indicator<\/p>\n<p>\u00a0<strong>CONCENTRATION<br \/>\n<\/strong>The concentration of a solution is the amount of solute in a given volume of the solution.  It can be expressed as mol\/dm<sup>3<\/sup> or g\/dm<sup>3<\/sup>.<\/p>\n<p>\u00a0<strong>Molar concentration<br \/>\n<\/strong>The molar concentration of a compound is one which contains one mole or the molar mass of the compound in 1dm<sup>3<\/sup> of the solution. Unit of molar concentration is mol\/dm<sup>3<br \/>\n<\/sup><br \/>\n\u00a0<strong>Mass concentration<br \/>\n<\/strong>The mass concentration of a compound is the mass of the compound contained in 1 dm<sup>3<\/sup> of solution. The unit is g\/dm<sup>3<br \/>\n<\/sup><br \/>\n\u00a0<strong>Relationship between Molar concentration and Mass concentration<br \/>\n<\/strong><img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0758_Week4SS2Th4.png\" alt=\"\"\/>Concentration = number of moles  = n\/V\u2026\u2026\u2026\u2026\u2026\u2026(i)<br \/>\nvolume<br \/>\nNumber of moles, n = C x V \u2026\u2026\u2026\u2026\u2026\u2026\u2026\u2026..(ii)<br \/>\nBut, number of moles, n= m\/M<br \/>\nWhere M = molar mass and m = mass<br \/>\nSubstituting n=m\/M into \u2026\u2026.(ii)<br \/>\nWe have m\/M = C x V<br \/>\nThat is, m\/V = C x M<br \/>\nBut m\/V = mass concentration<br \/>\nTherefore, mass concentration = molar concentration x molar mass = C x M<\/p>\n<p>\u00a0<strong>TITRATION REPORT<br \/>\n<\/strong><\/p>\n<div>\n<table>\n<tbody>\n<tr>\n<td><strong>Burette reading in (cm3)<\/strong><\/td>\n<td><strong>Rough<\/strong><\/td>\n<td><strong>1<sup>st<\/sup> titration<\/strong><\/td>\n<td><strong>2<sup>nd<\/sup> titration<\/strong><\/td>\n<td><strong>3<sup>rd<\/sup> titration<\/strong><\/td>\n<\/tr>\n<tr>\n<td>Final burette reading<\/td>\n<td>23.40<\/td>\n<td>23.20<\/td>\n<td>28.20<\/td>\n<td>34.10<\/td>\n<\/tr>\n<tr>\n<td>Initial burette reading<\/td>\n<td>0.00<\/td>\n<td>10.00<\/td>\n<td>05.00<\/td>\n<td>11.00<\/td>\n<\/tr>\n<tr>\n<td>Volume of acid used (titre)<\/td>\n<td>23.40<\/td>\n<td>23.20<\/td>\n<td>23.20<\/td>\n<td>23.10<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>\u00a0<img decoding=\"async\" align=\"left\" src=\"https:\/\/ecolebooks.com\/nigeria\/wp-content\/uploads\/9jalessonsimages\/100523_0758_Week4SS2Th5.png\" alt=\"\"\/>Average volume of acid used =  23.20 + 23.20 + 23.10<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0       3<br \/>\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0= 23.17cm<sup>3<br \/>\n<\/sup><br \/>\n\u00a0<strong>GENERAL EVALUATION\/REVISION<br \/>\n<\/strong><\/p>\n<ol>\n<li>Which substance is added to the base during titration experiment?<strong><br \/>\n\t\t\t<\/strong><\/li>\n<li>What is the colour of methyl orange in a base?\n<\/li>\n<li>What is the point at which the titration experiment appears to complete called?\n<\/li>\n<li>State three differences between electrolytic cell and electrochemical cell\n<\/li>\n<li>Calculate the standard e.m.f of a cell given that the e.m.f of Zn<sup>2+<\/sup>\/Zn and Cu<sup>2+<\/sup>\/Cu are -0.76V and +0.34V respectively\n<\/li>\n<\/ol>\n<p>\u00a0<strong>READING ASSIGNMENT<\/strong>: New School Chemistry SSS by O. Y. Ababio (6<sup>th<\/sup> edition) pages 165-168<strong><br \/>\n\t\t<\/strong><br \/>\n\u00a0<strong>WEEKEND ASSIGNMENT<br \/>\n<\/strong><strong>SECTION A: <\/strong>Write the correct option ONLY<br \/>\n1.\u00a0\u00a0\u00a0\u00a0The indicator used when titrating a weak acid against a strong base isA. methyl orange B. phenolphthalein C. methyl redD. any indicator<br \/>\n2.\u00a0\u00a0\u00a0\u00a0The colour of phenolphthalein in acids is   A. blue    B. red    C.colourlessD. yellow<br \/>\n3.\u00a0\u00a0\u00a0\u00a0Which of the following formulae is direct for amount n? A. n=C\/p B. n=M\/m C. n=C x V D. n=C x m<br \/>\n4.\u00a0\u00a0\u00a0\u00a0The mass concentration of a substance can be expressed as A. mass\/densityB. molar concentration\/molar mass     C. mass\/volume D. number of moles x volume<br \/>\n5.\u00a0\u00a0\u00a0\u00a0At the end point there is A. a colour change     B. no change of colourC. decrease in mass     D. an increase in mass<\/p>\n<p>\u00a0<strong>SECTION B<br \/>\n<\/strong><\/p>\n<ol>\n<li>\n<div>Define the following terms (a) molar concentration (b) Equivalent point\n<\/div>\n<\/li>\n<li>\n<div>160cm<sup>3<\/sup> of distilled water is added to 40cm<sup>3<\/sup> of 0.500mol\/dm<sup>3<\/sup> H<sub>2<\/sub>SO<sub>4 <\/sub>solution. Determine the concentration of the diluted solution.\n<\/div>\n<\/li>\n<\/ol>\n<p><strong><br \/>\n\t\t<\/strong>\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u00a0WEEK FOUR TOPIC: ACID\/BASE REACTIONS CONTENT Preparation of Standard Solutions. Indicators Calculations based on Acid-Base&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,268],"tags":[],"class_list":["post-3358","post","type-post","status-publish","format-standard","hentry","category-posts","category-third-term-ss2-chemistry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/3358","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/comments?post=3358"}],"version-history":[{"count":1,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/3358\/revisions"}],"predecessor-version":[{"id":3359,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/posts\/3358\/revisions\/3359"}],"wp:attachment":[{"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/media?parent=3358"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/categories?post=3358"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ecolebooks.com\/nigeria\/wp-json\/wp\/v2\/tags?post=3358"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}