CHEMICALS AND CHEMICAL CHANGE Chapter 5.1 BLM 5.1a, 5.1b

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 particle of matter

PHYSICAL CHANGE – a change in a substance which does not produce a new substance. Easy to reverse Ex. Melting ice CHEMICAL CHANGE – a change in a substance which does produce a new substance. Difficult to reverse Ex. Match burning

Classification of matter

Classification of matter

Classify each substance as 1) A pure substance or a mixture, and 2) An element, molecule, heterogeneous mixture or homogeneous: a) Glass of milk b) Spoonful of sugar c) A bar of gold d) Orange juice with pulp

Science 10 – Nov. 3rd Classify each reaction as a physical or chemical reaction: a) Butter melting b) Cheese molding c) Breaking a chocolate bar in half d) Burning toast

Science 10 – Nov. 3rd Classify each substance as 1) A pure substance or a mixture, and 2) An element, molecule, heterogeneous mixture or homogeneous: a) Glass of milk b) Spoonful of sugar c) A bar of gold d) Orange juice with pulp

Physical Reaction vs. Chemical Reaction Physical reactions are easy to reverse while chemical reactions are not. Ex “When ice melts is it easy to reverse that reaction? Burning a match?”

Physical Trait vs. Chemical Trait Physical traits are either simple observations or things having to do with physical reactions. Color, smell, size, mass, boiling point, melting point. Chemical traits have to do with chemical reactions. Will it catch on fire? Ability to react with other chemicals. Stable or unstable.

Science 10 – Nov. 1st 1) Classify each as 1) Pure substance or mixture, then 2) Element, compound, homogeneous mixture or heterogeneous mixture. Sugar Copper wire Air Orange juice w/ pulp Orange juice w/o pulp

Science 10 – Nov. 1st 2) Classify each as a physical change or a chemical change: Food rotting Breaking a carrot in half Water boiling Making toast Dissolving salt into water

Science 10 – Nov. 1st 3) Classify each as a physical trait or chemical trait: Water freezes at 0oC Ethanol is a clear liquid Gold does not react with acid Aluminum is a malleable metal Mercury metal is a liquid at room temperature

HOMEWORK QUESTIONS Page 175 QUESTIONS: #1,2,4,5,6,7 Explain in your own words the difference between element, atom, molecule and compound. Work on project

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

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

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 1000C. D) electric current can split water into hydrogen and oxygen gases

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? A chemical change has occurred because new substances were 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 )