Concetti Chiave
- Matter exists in three states: solid, liquid, and gas, each with distinct properties regarding shape and volume.
- State changes occur due to variations in temperature and pressure, including melting, boiling, condensation, and solidification.
- Sublimation is a unique transition where a solid directly becomes a gas without passing through a liquid state.
- A pure substance is classified as an element if it cannot be divided into simpler substances, or a compound if it can be.
- Elements are further categorized based on properties into metals, non-metals, and semi-metals.
States of Matter
Matter is made of different substances, each of them having its own typical properties.Matter can be found as a solid,if it has its own shape and volume,as a liquid,if it has its own volume,but assumes the shape of the recipient,or as a gas,if it has neither its own shape nor volume.Matter can change its physical state as a consequence of variations in temperature and pressure and such transformations are called state changes or state transitions.These transitions are melting,when a solid becomes a liquid,boiling,when a liqiuid becomes turbulently a gas.The opposite state changes are called condensations (gas to liquid) and solidification (liquid to solid).Lastly,sublimation takes place when a solid directly becomes a gas.Moreover a pure substance can be an element,if it cannot be divided into simpler substances,or a compound,if it is possible to divide into two or more substances.According to their properties,elements can finally be classified into metals,non-metals and semi-metals.