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| Question | Answer |
| What are Elements? | Simple substances that cannot be split up in chemical reactions. |
| What are the smallest particles of an element that can exist? | Atoms |
| What does each element have? | Chemical symbols (e.g. O for oxygen) |
| Where are all the symbols and names for all the known elements are shown? | In the periodic table. |
| What does a compound contain? | Two or more elements joined together by bonds. |
| Some elements have their atoms joined to each other in small groups called...? | Molecules |
| What does the chemical formula of a compound tell you? | The ratio of atoms of each element that are bonded together. |
| The properties of a compound are... | different from the elements that make it up. |
| How can chemicals be made to react? | By mixing them with other chemicals, or by using heat or electricity. |
| What are the 2 ways you can tell that a chemical reaction has occurred? | 1. Colour change 2. When a gas is given off |
| Most chemical reactions also involve an _______ ______. This is usually in the form of ____, for example in burning (combustion). | 1+2. Energy change 3. Heat |
| What is always formed in a chemical reaction? And are they easily reversible? | A new substance and they are irreversible. |
| How do some chemical reactions take place? | By mixing substances together (e.g. when a solid forms by mixing two liquids in a precipitation reaction). |
| What do other chemical reactions need to start off? | Energy (e.g. when some compounds are broken up, decomposed, by heat). |
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