Neutralisation - Shortened PPT PDF

Neutralisation  Agenda 1. Learn about the reaction between an acid and an alkali, known as Page 30 - 31 neutralisation. 2. Know the general equation for reactions between acids and alkalis. 3. Practice naming salts from the names of ac...

Neutralisation  Agenda 1. Learn about the reaction between an acid and an alkali, known as Page 30 - 31 neutralisation. 2. Know the general equation for reactions between acids and alkalis. 3. Practice naming salts from the names of acids and alkalis. Review  Review Where would you find an acid on the pH scale? A. Between 0 - 7 B. Exactly 7 C. Between 7 - 14  Review Where would you find an alkali on the pH scale? A. Between 0 - 7 B. Exactly 7 C. Between 7 - 14  Review Match the common acids and alkalis: Acids Alkalis  Review To testWhat is an indicator the acidity used or alkalinity of for? a solution.  Review Give 2 examples Litmus of pH indicators. and Universal Indicator Vocabulary  Vocabulary The substances which take part in a 1 Neutralisation 2 chemical reaction. A chemical reaction in which an acid and a 2 Reactant 1 base react to form water and a salt. The new substances which are formed in 3 Product 3 a chemical reaction. A compound formed during the 4 Salt 4 neutralisation of an acid. Neutralisation  What is Neutralisation? Neutralisation is when an acid and an alkali react to form a neutral product. Neutralisation is a chemical reaction because a new substance is created. The neutral product that is created is called a salt. Water is often also created. Neutralisation is an exothermic reaction (gives out heat). Neutralisation reduces the damage an acid or alkali solution can do.  Neutralisation Reaction In neutralisation, an acid and an alkali react to create a salt and water. Write neutralisation as a chemical reaction: Acid + Alkali Salt + Water Reactants are the Products are the new substances needed substances made. for the reaction. Neutralisation  Hydrogen Chloride Neutralisation Sodium Hydroxide Sodium Chloride Water (H20) (HCl) (NaOH) (NaCl) Acids have more Alkalis have more H+ (positive) ions. OH- (negative) ions. Water is made when the H+ ions combine with the OH- ions. The remaining ions combine to create a Salt.  Neutralisation For neutralisation, the acid and alkali need to be of the same strength. Strong Strong Acid + Alkali Salt + Water Weak Weak Acid + Alkali Salt + Water  Neutralisation 1. To neutralise a solution, you first need to know if it is acidic or alkali. litmus paper test will tell you if a solution is acidic 2. A _________________ or alkali, but not by how much. universal indicator to tell you how strong or 3. Use an _________________ weak the solution is (pH number). 4. Once the level of acidity or alkalinity is known, we can neutralise it with. choose an equal substance to ___________  Neutralisation Examples of common acids being neutralised HCl + NaOH → NaCl + H2O Hydrochloric Sodium Sodium Water acid hydroxide chloride HNO3 + KOH → KNO3 + H2O Nitric Potassium Potassium Water acid hydroxide nitrate HCl + KOH → KCl + H2O Hydrochloric Potassium Potassium Water acid hydroxide chloride  Making Salts The combination of metals and metal carbonates with acid creates salts. Metal + Acid Salt + Hydrogen Sodium + Hydrochloric Acid = Sodium Chloride + Hydrogen (2Na + 2HCl = 2NaCl + H2) Carbonated Salt + Water + Metal + Acid Carbon Dioxide Sodium Carbonate + Hydrochloric Acid = Sodium Chloride + Water + Carbon Dioxide (Na2CO3 + 2HCl = 2NaCl + CO2 + H2O) Neutralising Acids  Neutralising Stings Wasp stings are alkali. To neutralise them we can use an acid like vinegar. Bee stings are acidic. To neutralise them we can use an alkali like baking soda.  Neutralising in the Body Stomach acid helps digest our food, but too much can make us sick. To neutralise the extra acid, we take medicine that is alkaline. The bacteria in plaque produce acids which damage our teeth. To neutralise the acid and reduce plaque we use toothpaste which contains an alkali (like baking soda).  Neutralising Acid Rain Acid rain can make soil and bodies of water (lakes, rivers & steams) acidic. To neutralise the soil, farmers add an alkali like lime, to the soil. Lime can also be added to bodies of water to neutralise the acid from the rain.  Textbook Practice Page 30 - 31; Question 1 - 4 Page 30 - 31 1a) pH lower than 7 b) pH greater than 7 2a) Cauliflower and mushrooms grow well in neutral soil. b) Leeks most likely won’t need lime in the soil. 3a) Flask X contains an acid. b) You can tell by the color in the flask. 4a) Red color indicates a strong acid. b) Approximately 11-12 pH. Worksheet  Neutralisation is when an acid and an alkali react to form a neutral product. Products are the new substances made. Reactants are the substances needed for the reaction. The combination of metals and metal carbonates with acid creates salts. Neutralisation acid alkali neutral Neutralisation reduces the damage an acid or alkali solution can do. acid alkali salt water Universal indicators can be used to monitor the process HCl NaCl  HCl + NaOH → NaCl + H2O Hydrochloric Sodium Sodium Water acid hydroxide chloride HNO3 + KOH → KNO3 + H2O Nitric Potassium Potassium Water acid hydroxide nitrate HCl + KOH → KCl + H2O Hydrochloric Potassium Potassium Water acid hydroxide chloride Wasp stings, which are naturally alkaline, can be neutralised using vinegar. STEM: Neutralization  STEM: Neutralization Let’s perform a neutralization reaction on an acid to weaken it’s acidity Procedure: 1) Determine which solution is an acid and an alkali using an indicator. 2) After determining the acid, slowy add the alkali to the acid until you get a sligh greenish, yellow color. (Be careful as the color transition happens instantly!) STEM: Neutralization Review Quiz  Review What will the product of a neutralisation reaction be? A. Acidic B. Neutral C. Alkali  Review Complete the neutralisation formula: Acid + Alkali Salt + Water  Review Acids have more H+ ions, and alkalis have more OH- Describe the ions present in acids and alkalis. ions.  Review Name the salt created in the neutralisation reaction: A. Sodium hydrocloric Sodium bicarbonate (baking soda) B. Bicarbonate ethanol C. Sodium ethanoate Ethanoic acid (vinegar)  Review Neutralising bee stings, stomach acid, tooth plaque or Give an example of neutralising acid in everyday life. acid rain... What did we do today? 1. Learn about the reaction between an acid and an alkali, known as neutralisation. 2. Know the general equation for reactions between acids and alkalis. 3. Practice naming salts from the names of acids and alkalis.  Next week: We will study Introduction to Reproduction Bring your Biology textbook. End of Class