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Grade 9 Science
Chemistry Unit Test
| Question | Answer |
|---|---|
| What is The Particle Theory of Matter? | 1.All matter is made up of tiny particles 2.Different substances are made up of different types of particles 3.Particles are in a constant state of motion 4.The higher the temperature the faster the particles move 5.Particle attract each other |
| What is Matter? | Matter is anything that has mass and takes up space. Ex:. Water Non example: Sound |
| What is a Pure Substance? | Pure substances are composed of only one type of particle. |
| What are the 2 types of pure substances? | Elements and Compounds |
| What is an Element | Elements are composed of only one type of atom. Elements can not be broken down. All Elements can be found on the periodic table. |
| What is a Compound? | Compounds are composed of two or more different types of atoms bonded together into molecules. Compounds can be separated in a chemical reaction. |
| What is a Mixture? | A mixture is composed of two or more pure substances mixed together. It is composed of different types of particles. A mixture can be separated by physical means |
| What are the 2 types of Mixtures? | Solutions and Mechanical Mixtures. |
| What is a Solution? | Solutions are one visible phase. ex: Gatorade and salt water. |
| What is a Mechanical Mixture? | A Mechanical Mixture is two or more visible phases. ex: Pizza, salt and papper |
| What are Physical Properties? | Physical Properties are the characteristics of a substance that can be observed using our five senses, and without changing the substance into another substance. Ex: Colour, Odour, Texture, Lustre, Clarity, State, Viscosity. |
| What are Chemical Properties? | Chemical Properties are observations that are made when a substance either reacts or does not react with another substance. Ex: acids will dissolve metals. |
| What is a Physical Change? | A Physical Change is a change which does not alter the composition of the starting substance or substances, and does not produce any new substances. |
| Evidence that a Physical Change has occurred. | 1.There is a change in size or shape. 2.A solid dissolving in a liquid to create a solution. 3.There is a change of state. 4.The change is reversible |
| What is a Chemical Change? | A Chemical Change is a change that alters the composition of the starting substance or substances, and produces one or more new substances in the process. |
| Evidence that a Chemical Change has occurred. | 1.There is a change in colour 2.There is a change in odour 3.Bubbles form (not as a result of the substance being heated) 4.A new solid (precipitate) forms in a liquid 5.There is a change in temperature or light *2 clues to indicate a chemical change |
| What is a Molecule? | A Molecule is a group of Atoms that are chemically joined together. |
| What is a Molecular Element? | A Molecular Element is a molecule made up of the same type of Atoms. |
| Characteristics of Metals. | Colour: silver/grey Lusture: Shiny Malleable: Yes Able to Conduct Electricity: Yes Magnetic: No |
| Characteristics of Non-Metals. | Colour: Wide range (commonly not silver or grey) Lusture: Dull Malleable: No Able to conduct electricity: No Magnetic: No |
| How Democritus contributed to Atomic Theory. | Around 400 BCE, Democritus proposed that all matter can be divided smaller and smaller until a single indivisible particle (the Atom) is reached. He also proposed that Atoms are of different sizes, in constant motion, and separated by empty spaces. |
| How Aristotle contributed to Atomic Theory. | Around 450 BCE, Aristotle supported an earlier idea that all matter is made up of 4 substances: earth, water, air, and fire. These substances were thought to have 4 specific qualities: dry, wet, cold, and hot. |
| How Dalton contributed to Atomic Theory. | 1807: -All matter is made up of tiny, invisible particles called Atoms -All Atoms of an element are identical -Atoms of different elements are different -Atoms are rearranged to form new substances in chemical reactions but are never created/destroyed |
| How J.J. Thompson contributed to Atomic Theory. | 1897 Thompson's Idea: Extremely small negatively charged particles could be emitted by very hot materials. Theory: Atoms have negative electrons, the rest of the atom is a positively charged sphere. Negative electrons are evenly distributed in an atom |
| How Rutherford contributed to Atomic Theory. | 1909 The Gold Foil Experiment Predicted positively charged particles shot at a thin piece of gold foil would pass thru the foil, and some would be slowed down/deflected at very small angles. |
| Rutherford Atomic Theory continued | When the experiment was performed some particles were deflected at very large angles, as though they had collided with a small, concentrated, positively charged central mass inside the atom. |
| Rutherford Atomic Theory part 3 | The centre of the atom is called the nucleus, has a positive charge, contains most of the atoms mass, and occupies a small space. The nucleus is surrounded my negatively charged electrons, and most of the atom is empty space. |
| How Bohr contributed to Atomic Theory. | 1913 Bohr discovers: Electrons orbit the nucleus of an atom. Each electron in the orbit has a certain amount of energy. The further from the nucleus the greater the energy. Electrons can't be between orbits, but can jump to & from orbits. |
| Bohr Atomic Theory continued. | They release energy as light when they jump from higher to lower orbits. Each orbit holds a certain number of electrons. First hold 2, second holds 8, and third holds 8. |
| How Chadwick contributed to Atomic Theory. | Discovered Planetary Model in 1932 Found a particle that could penetrate & disintegrate atom w/ strong power. Atom is an empty sphere w/ a tiny dense nucleus Nucleus contains positively charged protons & neutral particles called neutrons |
| Chadwick Atomic Theory continued. | Negatively charged electrons circle rapidly through the empty space around the nucleus. A neutral atom will have the same number of protons as electrons. |