Pure Elements Grade 8 PDF

# Advance International Academy ## Pure Elements ### Grade 8 ## What are Pure Elements? - A pure element consists of only one type of atom. - Example: Pure gold is made of only gold atoms. ## Gold Purity - Gold purity is measured in carats. - 24 carat gold: Pure gold (100% purity) - 18 carat gold:...

# Advance International Academy ## Pure Elements ### Grade 8 ## What are Pure Elements? - A pure element consists of only one type of atom. - Example: Pure gold is made of only gold atoms. ## Gold Purity - Gold purity is measured in carats. - 24 carat gold: Pure gold (100% purity) - 18 carat gold: 75% gold, 25% other metals - 9 carat gold: Lower purity with more alloy metals ## Silver Purity - Silver purity is measured in parts per thousand. - Marked 925: 92.5% pure silver - Marked 900: 90% pure silver - Higher the number, greater the purity. ## Diamonds and Their Purity - Pure diamonds are made entirely of carbon atoms and are colorless. - Colored diamonds form when other elements mix with carbon: - Yellow: Nitrogen replaces some carbon atoms. - Blue: Boron replaces some carbon atoms. - Green: Rare, caused by nitrogen, nickel, or hydrogen impurities. ## Structure and Purity - Diamonds are made from carbon atoms arranged in a specific structure. - Pure diamonds contain only carbon atoms and are colorless and translucent. ## Seawater: Composition and Properties ## What is Seawater? - Seawater is a mixture of water and dissolved salts. - Water makes up 96.5% of seawater. - Salts make up 3.5%, primarily sodium chloride. - Seawater can be processed to extract salt by evaporation. ## Salt Composition in Seawater - The salt content in seawater consists of: - Sodium chloride: 68% - Magnesium chloride: 14.6% - Sodium Sulfate: 11.4% - Calcium chloride: 3.1% - Other salts: 2.9% ## Extraction and Importance - Importance of Seawater: - Provides salt for consumption and industry. - Essential for marine ecosystems. - Can be processed for fresh water through desalination. ## Pure Products in Chemistry ## What Are Pure Products? - Pure products in chemistry are substances without impurities. - Example of a single product reaction: - Magnesium + Oxygen → Magnesium Oxide - Example multiple product reactions: - Silver nitrate + Sodium chloride → Sodium nitrate + Silver chloride ## Importance and Safety Measures - Importance - Ensures effectiveness in medicine and food products. - Prevents harmful side effects due to impurities. - Safety Measures: - Always wear safety glasses. - Handle chemicals with care.