Flashcards
8G ~ elements, mixtures and compounds
Cards in this deck (14)
- 1What are Elements?Simple substances that cannot be split up in chemical reactions.
- 2What are the smallest particles of an element that can exist?Atoms
- 3What does each element have?Chemical symbols (e.g. O for oxygen)
- 4Where are all the symbols and names for all the known elements are shown?In the periodic table.
- 5What does a compound contain?Two or more elements joined together by bonds.
- 6Some elements have their atoms joined to each other in small groups called...?Molecules
- 7What does the chemical formula of a compound tell you?The ratio of atoms of each element that are bonded together.
- 8The properties of a compound are...different from the elements that make it up.
- 9How can chemicals be made to react?By mixing them with other chemicals, or by using heat or electricity.
- 10What are the 2 ways you can tell that a chemical reaction has occurred?1. Colour change
2. When a gas is given off - 11Most chemical reactions also involve an _______ ______. This is usually in the form of ____, for example in burning (combustion).1+2. Energy change
3. Heat - 12What is always formed in a chemical reaction? And are they easily reversible?A new substance and they are irreversible.
- 13How do some chemical reactions take place?By mixing substances together (e.g. when a solid forms by mixing two liquids in a precipitation reaction).
- 14What do other chemical reactions need to start off?Energy (e.g. when some compounds are broken up, decomposed, by heat).