CHEMICALS AND CHEMICAL CHANGE Chapter 5.1 BLM 5.1a, 5.1b _type=&aq=2&oq=alkali+ _type=&aq=2&oq=alkali+

Chemicals and chemical Change CHEMISTRY – is the study of matter, its changes and its properties MATTER – is anything that has mass and takes up space ATOM – the smallest unit of matter

Physical property: Physical characteristics of the substance – observed by senses. Ex. color, density, hardness, etc. Chemical properties: Properties that describe how a substance changes into a completely different substance. Ex. Flammability and corrosion/oxidation

HANDOUT 5.1a Use the following labels and pages 172 – 173 to complete the handout Chemical changes, pure substances (x2) C, O, H 2 O, O 2 Heterogeneous mixtures, elements, atoms (x2), NaCl, chemical formulas, chemical symbols, physical changes, solutions, molecules, compounds

Heterogeneous Mixture Pure Substance Physical Changes Solutions ElementsCompounds Chemical Symbols Atoms Molecules Chemical Formulas Pure Substance C O O2O2 NaClH2OH2O Chemical Changes Atoms

PHYSICAL CHANGE – a change in a substance which does not produce a new substance. EXAMPLE: melting ice CHEMICAL CHANGE – a change in a substance which does produce a new substance. EXAMPLE: match burning

HANDOUT 5.1b Use the following labels and pages 173 – 174 to complete the handout Rusting/corrosion, difficult to reverse, water vapour, turns cloudy, new colour, reactants, pops, turns pink, oxygen (x2), products, precipitate, carbon dioxide, bursts into flames, heat or light, hydrogen

Reactants Products Corrosion or Rusting Oxygen Tough to reverse Energy Given off Precipitate forms H2H2 O2O2 H2OH2OCO 2 Pops Bursts into Flames Turns Pink Turns Cloudy Colour Change

CLASS/HOMEWORK QUESTIONS Page 175 Page 175 QUESTIONS: #1-2,4-7 QUESTIONS: #1-2,4-7

SOLUTIONS TO HOMEWORK QUESTIONS Q1 – classify each of the following as a pure substance or a mixture A) soapy water MIXTURE B) hydrogen gas PURE SUBSTANCE C) sodium chloride PURE SUBSTANCE

QUESTION 2 Classify each of the following as an element or a compound. A) hydrogen ELEMENT B) potassium carbonate COMPOUND C) water COMPOUND D) Mg ELEMENT

QUESTION 4 Classify each of the following as a physical property or a chemical property. A) Gasoline is a clear pink solution PHYSICAL PROPERTY B) Gasoline burns in air CHEMICAL PROPERTY C) Water boils at C. PHYSICAL PROPERTY D) electric current can split water into hydrogen and oxygen gases CHEMICAL PROPERTY

QUESTION 5 When aluminum metal is added to hydrobromic acid, hydrogen gas and an aluminum bromide solution are formed. A) What kind of change has occurred? Chemical, bubbles formed, new substance made

QUESTION 5 When aluminum metal is added to hydrobromic acid, hydrogen gas and an aluminum bromide solution are formed B) Which substances are the reactants and which are the products? Reactants – Aluminum and Acid Products – Hydrogen + Aluminum Bromide

QUESTION 6 Describe the chemical tests that can be used to identify the following gases. A) hydrogen a flaming wooden splint causes a “pop” B) Oxygen a glowing wooden splint relights (bursts into flame)

QUESTION 6 C) Carbon Dioxide A burning wooden splint extinguishes, OR when the gas is bubbled through limewater, the limewater changes from a clear, colourless solution to a cloudy white liquid (a precipitate is formed)

QUESTION 6 d) Water Vapour Changes the colour of cobalt chloride test paper from blue to pink

QUESTION 7 When sodium carbonate is added to water, the sodium carbonate dissolves. When hydrochloric acid is added to the solution, the solution fizzes. What kinds of changes have occurred?

QUESTION 7 - ANSWER When sodium carbonate dissolves in water it is a physical change A chemical change happens when gas is formed after hydrochloric acid is added ( fizz / Bubbles )