Chemistry Exam Review January 2025 Answers PDF

SCN1W1 Grade 9 Science Chemistry: Matter, Periodic Table and Chemical Compounds 1.​ List the five parts of the Particle Theory of Matter. ​ All matter is made up of tiny particles, known as atoms and molecules ​ Different substances are made up of different kinds of particles ​ Particles a...

SCN1W1 Grade 9 Science Chemistry: Matter, Periodic Table and Chemical Compounds 1.​ List the five parts of the Particle Theory of Matter. ​ All matter is made up of tiny particles, known as atoms and molecules ​ Different substances are made up of different kinds of particles ​ Particles are in constant random motion ​ Particles attract each other. The forces of attraction are stronger when the particles are closer together ​ Particles move faster when its temperature increases 2.​ Fill in the Classification of Matter chart. Provide an example for each. 3.​ Indicate whether each of the following is a pure substance (P) or a mixture (M). P element or compound​ ​ ​ M solution​ ​ ​ P salt M two or more visible phases​ ​ M alloys​ ​ ​ M lemonade P cannot be separated by physical means Page 1 4.​ Define the following terms. Term Definition a) physical change Change in the physical form of the substance without changing the ​ chemical composition. b) chemical change Changes in a substance into a new substance that has different physical and chemical properties and a new chemical formulae. c) physical property Characteristics that can be observed without changing the physical composition of the substance ​ ​ d) chemical property Characteristics that are observed when the chemical composition of a ​ ​ substance changes as it turns into a new substance 5.​ Match each statement with the correct physical property. Answer Physical property Statement h Texture a)​ Can you see through it? l Ductility b)​ Can be hammered into thin sheets k Luster c)​ Temperature when a solid turns to liquid i Taste d)​ Temperature when a liquid becomes gas g State e)​ How easy a liquid flows j Brittleness f)​ Can it dissolve? c Melting point g)​ Solid or liquid …. a Clarity h)​ It is smooth or gritty? b Malleability i)​ It is sharp or burnt or spicy? e Viscosity j)​ Tendency to break under stress f Solubility k)​ Shiny or dull? d Boiling point l)​ Can be made into wires 6.​ List 5 clues that a chemical change has occurred. ​ Energy change (light and/or heat) ​ Formation of gas (bubbles or fumes) ​ Precipitation (new solid) ​ Change in colour ​ Change in odour Page 2 7.​ Indicate whether each of the following is a chemical change (C) or a physical change (P). a) C a new substance formed b) P a change in state: e.g. melting, freezing, vaporization c) P change is reversible d) P change in shape or form e) C change is not reversible by physical means f) P ice cream melting g) C methane gas produced from decomposition h) C fireworks i) C baking a cake j) P cutting the lawn k) P inflating a balloon l) C incandescent light bulb 𝑚 8.​ a) Write the formula for calculating density. 𝐷 = 𝑉 b)​ A sample of metal has a mass of 15 g and a volume of 2.0 cm3. Calculate the density of the sample. Show all your work using GRASS. G (givens) m=15 g V=2.0 cm3 R (required) D=? A (analysis) D = m/V S (substitute D=15g/2.0 cm3 = 7.5 g/cm3 and solve) S (sentence) The density of the metal sample is 7.5 g/cm3 Page 3 9.​ a) Use the periodic table to determine the names of the elements given by their atomic symbols below. Symbol Ca Cl Mg Na Name calcium chlorine magnesium sodium b)​ Which of the elements from a) does not have a name that matches its atomic symbol? Na 10.​Name the following families of the Periodic table. a)​ Group 2 ​ Alkaline Earth Metals b)​ Group 18​ Noble Gases b)​ Group 1​​ Alkali Metals 09- c)​ Group 17​ Halogens 11.​Distinguish between an atom, a molecule and a compound. An atom is a single, smallest particle of an element composed only with a nucleus and orbiting electrons. A molecule is made up of two or more atoms. A compound is made up of two or more elements. 12.​a) Define the following terms. Term Definition atomic number The number of protons in the atom’s nucleus atomic mass Sum of protons and neutrons in the nucleus ​ b)​ Using the Periodic table explain how you would determine each of the following quantities? # of protons Atomic number # of electrons Atomic number (if neutral) Page 4  # of neutrons Atomic mass - atomic number 13.​Complete the following chart. Element Symbol Standard Atomic # Atomic # of # of # of Atomic Mass Protons Electrons Neutrons Notation Lithium Li 7 𝐿𝑖 3 7 3 3 4 3 Fluorine F 19 𝐹 9 19 9 9 10 9 mercury Hg 201 𝐻𝑔 80 201 80 80 121 80 Sulfur S 32 𝑆 16 32 16 16 16 16 Potassium K 39 𝐾 19 39 19 19 20 19 Calcium Ca 40 𝐶𝑎 20 40 20 20 20 20 14.​Draw Bohr- Rutherford diagrams of the sodium and chlorine atoms. Label and number all the subatomic particles. Then draw the ion of each lithium nitrogen lithium ion nitrogen ion Page 5 15.​Draw the Bohr-Rutherford diagrams to show how the compound beryllium fluoride is formed. Formula: BeF2 16.​a) Define the term valence electrons. ​ Electrons on the outer filled shell of an atom. b)​ How many electrons does an atom want to have in its outer shell to be stable? 8 (2 for He and 0 for H) c)​ How many electrons do elements in the following families gain or lose to become stable? Group 7​ gain 1 Group 8​ does not lose or gain Group 1​ lose 1 Group 3​ lose 3 d)​ How many electrons do the following elements gain or lose to become stable? Na ​ lose 1 Cl​ gain 1 Mg​ lose 2 Ne ​ does not lost or gain e)​ Write the symbols for the ion that each element in d) forms. Na ​ Na+ Cl​ Cl- Mg​ Mg2+ Ne ​ Ne Page 6 17.​Define the following terms. Term Definition Ion A charged particle formed from an atom that has gained or lost valence electrons. Cation A positively charged ion Anion A negatively charged ion ionic bonding A bond formed between two oppositely charged ions 18.​Determine the number of each atom and its total in the following compounds. H2O​ ​ ​ ​ ​ Ca(OH)2​ ​ ​ ​ Mg3(PO4)2 19.​Determine the chemical formula and name the compound formed by each of the following pairs of ions. Ions Chemical Formula Name of Compound KF Potassium fluoride K+ & F- Li2S Lithium sulfide Li+ & S2- CaCl2 Calcium chloride Ca2+ & Cl- BeO Beryllium oxide Be2+ & O2- Al2O3 Aluminum oxide Al3+ & O2- Page 7 20.​Fill in the table with missing information. *Multivalent metals won’t be on the exam, but will be in grade 10! Compound Name Formula mercury (I) oxide Hg2O lead (IV) sulphide (simplified) PbS2 Magnesium bromide MgBr2 carbon dioxide CO2 Calcium phosphide Ca3P2 aluminum fluoride AlF3 potassium nitride K3N Cobalt (III) iodide CoI3 Barium oxide BaO Copper (II) chloride CuCl2 Lithium sulfide Li2S Copper (I) bromide CuBr iron (III) nitride FeN Glucose C6H12O6 Page 8