5.1. Acids and Doses. Before You Read. Section. Summary. What are acids and bases? What is ph?

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1 Acids and Doses Textbook pages Summary Before You Read Many acids and bases can be found in your home. Describe one acid and one base that you are familiar with. Record your answer in the lines below. What are acids and bases? Many common pure substances can be classified according to whether they are acids or bases. Acids produce hydrogen ions (Hf) and bases produce hydroxide ions (OH-) when dissolved in solution. The concentration of hydrogen ions refers to the number of hydrogen ions in a specific volume of solution. Solutions with a high concentration of hydrogen ions are highly acidic. Similarly, solutions with a high concentration of hydroxide ions are highly basic. When an acidic solution is mixed with a basic solution, the solutions can neutralize each other, which means that the acidic and basic properties are in balance. What is ph? Testing the ph of a solution is a way of measuring its concentration of hydrogen ions, H(aq). The ph scale is a number scale that indicates how acidic or basic a solution is. Acids have a ph below 7 and bases have a ph above 7. Neutral solutions have a ph of 7. On the ph scale, one unit of change represents a 10-fold change in the degree of acidity or basicity. For example, a two unit drop in ph is a 102 or 100 times increase in acidity. 0? Create a Quiz After you have read this section, create a fivequestion quiz on acids. Answer your questions until you get them all correct. Reading Check What is the ph of a neutral solution? What are ph indicators? ph indicators are chemicals that change colour depending on the ph of a solution. Litmus paper can determine whether a solution is acidic or basic. Blue litmus paper turns red in an acidic solution (below ph 7). Red litmus paper changes to blue in a basic solution (above ph 7), 2008 McGraw-Hill Ryerson Limited 5.1 Acids and Bases MHR 81

2 Summary MHR 5.1 Acids and Bases 2008 McGraw-Hill Ryerson Limited can be named in several ways. Many compounds take on acidic properties only when mixed with water. If no state of Generally, the chemical formula for an acid starts with end with the suffix -ate (i.e., hydrogen carbonate, H2C0 can be changed by dropping hydrogen from the name How are acids and bases named? matter is given, the name may be begin with hydrogen, as Other acids that do not contain oxygen, such as hydrofluoric with the suffix -ite (i.e., hydrogen suiphite, H2SO3), then the Another naming system is followed when oxygen is present in the formula. s that begin with hydrogen and name can be changed to end with the suffix -ous acid (i.e., chemical formulas. Common names of bases include sodium hydroxide (NaOH) and magnesium hydroxide (Mg(OH) H2SO4(aq), also follow this naming system. as being aqueous (dissolved in water), a different name may in hydrogen chloride (HC1). However, if the acid is shown H (hydrogen) on the left hand side of the formula. Acids be used one that ends in -ic acid, as in hydrochloric acid. acid, HF(aq); nitric acid, HNO 3 (aq); and sulphuric acid, 2). sulphurous acid, H2S0 Bases generally have OH on the right hand side of their H2CO3(aq)). When the name begins with hydrogen and ends 3(aq)). and changing the suffix to -ic acid (i.e., carbonic acid, 3) the electrical properties of a solution can also be used to 0 indicators. Each determines ph within a different range. determine ph. Provide the name of a methyl orange, and methyl red are other common ph common ph indicator, 0 Reading Check Phenolphthalein, bromothymol blue, indigo carmine, A digital ph meter or ph computer probe that measures that turn different colours depending on the ph of the solution. A universal indicator contains a number of indicators

3 5.1 Summary What are the properties of acids and bases? Some of the properties of acids and bases are compared in the table below / Property Acid Base I Taste I Acids taste sour. Lemons, I Bases taste bitter. The CAUTION: Never taste I limes, and vinegar are quinine in tonic water is chemicals in the laboratory. common examples. one example. j I Touch Many acids will burn Bases feel slippery. CAUTION: Never touch your skin. Sulfuric acid.. Many bases will burn chemicals in the laboratory (battery acid) is one.. your skin. Sodium with your bare skin, example. hydroxide (lye) is one example. Indicator tests Acids turn blue litmus paper red. Phenolphthalein is colourless in an acidic solution. Bases turn red litmus blue. Phenolphthalein is colourless in slightly basic solutions and pink in moderate to strongly basic solutions. Reaction with some Acids corrode metals. No reaction metals, such as magnesium or zinc I Electrical conductivity Conductive Conductive!an71ethan7 Production of ions Acids form hydrogen Bases form hydroxide (H±) ions when ions when dissolved in solution. dissolved in solution. (0H) , What are some common acids and bases? Formula CH3COOH 4 H2S0 9 Mg(OH) Examples of uses ethanoic acid or acetic acid in vinegar sulphuric acid automobile batteries NaOH sodium hydroxide drain and overn cleaners magnesium hydroxide antacids HCI hydrochloric acid digestion in stomach 2008 McGraw-Hill Ryerson Limited 5.1 Acids and Bases MHR 83

4 How many different uses for salts can you name? Write your answers on the lines below. Before You Read Textbook pages Salts Summary salts Acids can also react with metals and carbonates to produce salts? Which other compounds react with acids to produce acid + base -+ salt + water HC1 + NaOH -, NaCl + H20 base) reaction. For example: water in a chemical reaction called a neutralization (acid from an acid. An acid and a base react to form a salt and in this section. Then use a 2008 McGraw-Hill Ryerson Umited 5.2 Salts MHR 89 to produce salts. Much of the carbon dioxide on the precipitation, the carbonates help to neutralize the acid. The most reactive metals are the alkali metals and dolomite, and calcite, which contain carbonate ions. When Sulphuric acid is one component of acid precipitation. carbonate rocks react with acids, such as those in acid the bottom of the columns react the most vigorously. surface of Earth is trapped in rocks, such as limestone, 2. Carbonates: Carbonates can also react with acids of the periodic table. Within these groups, the elements at alkaline earth metals, which appear on the extreme left 2HC1(aq) + Mg(s) - MgCl 2(aq) + H2(g) they usually release hydrogen gas, as shown below. 1. Metals: When metals react with acids to produce a salt, What is a salt? Reading Check the answers to the questions. different colour to highlight is made up of a positive ion from a base and a negative ion Highlight each question head be formed during the reaction of an acid and a base. A salt Identify Concepts In chemistry, salts are a class of ionic compounds that can Mark the Text What are salts? 5.2

5 H2S0 4 + CaCO 3 -* CaSO 4 + H20 + CO2 releases carbon dioxide gas, as shown below. The chemical reaction between this acid and carbonate This acid can react chemically with a base to form a salt. carbonic acid 2(g) (l) 4 H2C0 C0 3(aq) compound that contains a non-metal chemically combined with oxygen. A non-metal oxide, such as carbon dioxide, combines with water to form an acid. The base can then react chemically with an acid to form a 20(s) +H20(l) 4 2NaOH(aq)(a base) Na to form a base (see below). contains a metal chemically combined with oxygen. A What are oxides? Sectioii 5.2 L_ Reading Check An oxide is a chemical compound that includes at least one Which type of oxide oxygen atom or ion along with one or more other elements. combines with water to Both metals and non-metals can form oxides. form a base?. 1. Metal oxides: A metal oxide is a chemical compound that metal oxide, such as sodium oxide, combines with water sodium hydroxide salt. 2. Non-metal oxides: A non-metal oxide is a chemical 90 MHR 5.2 Salts 2008 McGraw-Hill Ryerson Limited

6 lines below. What do you think of when you hear the term organic? Outline your thoughts in the Before You Read Textbook pages Organic Compounds Summary structural formula molecular formula Shows a single ball-and-stick model space-filling model 2008 McGraw-Hill Ryerson Limited 5.3 Organic Compounds MHR 95 H-C-H I _- covalent bond _ CH4 recall on the back. on the front of the card and the name of the compound organic compounds. Write you remember common Create flash cards to help the information you want to as inorganic compounds. In almost all organic compounds, (with a few exceptions). All other compounds are referred to The carbon in organic compounds forms four bonds, carbon atoms are bonded to hydrogen atoms or other elements that are near carbon in the periodic table, especially nitrogen, oxygen, sulphur, phosphorus, and the halogens. Other elements, including metals and non-metals, may also be present. which enables it to form complex, branched-chain structures, different methods can be used to model these structures. These include the structural formula, the ball-and-stick ring structures, and even cage-like structures. Several model, and the space-filling model shown below. Organic compounds are any compounds that contain carbon Make Flash Cards What are organic compounds? 5.3

7 compound differ from an diagram. However, there are a few exceptions to this rule. How does an organic of the presence of carbon in its name, chemical formula, or Reading Check To recognize a compound as organic, look for an indication 96 MHR 5.3 Organic Compounds 2008 McGraw-Hill Ryerson Limited ofgasoline pentane C5H12 H H H H H CH3CH2CH2CH2CH3 Component H c t E H lighters butane C4H10 H H H H CH3CH2CH2CH3 Hand-held propane C3H8 H H H CH3CH2CH3 Camp fuel H C C H plastic ethane C2H6 H H CH3CH3 Manufacturing H C H heaters Formula Formula Structural Formula Model methane CH4 H CH4 Natural gas Molecular Structural Shortened Space-Filling Common Uses 1. Hydrocarbons: A hydrocarbon is an organic alcohols. the hydrocarbon molecule called methane (CH 4) which atoms. Other hydrocarbons are formed by linking two or more carbons together to make a chain. The first hydrogen. The simplest of all organic compounds is consists of a carbon atom bonded to four hydrogen five hydrocarbons are given in the table below. Two common organic compounds are hydrocarbons and compound that contains only the elements carbon and What are some common organic compounds? Certain compounds that contain carbon are classified as inorganic carbon compounds. These include any compounds and oxides (i.e., C0 2, CO). 0 that contain carbonates, (i.e., CaCO 3); carbides, (i.e., SiC); inorganic compound? 5.3 :

8 that contains C, H, and 0 in a specific structure. The table below shows some common alcohols. formula for ethanol. 2. Alcohols: An alcohol is one kind of organic compound Provide the molecular Reading Check 2008 McGraw-Hill Ryerson Limited 5.3 Organic Compounds MHR 97 1 alcohol 9 H C C C -H isopropyl C3H80 H I (CH 3)CH 2OH Sterilizer Cleaner, ---- HH I, H. C C.--O H ethanol C2H60 HH CH3CH2OH Fuel H C--O H Formula Formula methanol 0140 I Cl-1 30H Solvent Molecular Structural Structural Formula Model Shortened Space-Filling Common Use 5.3 F