Differences Between Compounds, Molecules & Mixtures

• What are the three important terms to understand when discussing how atoms exist in the real world?

  Molecules, mixtures, and compounds
• What is a molecule?

  A group of two or more atoms
• How do oxygen molecules exist in the air?

  As pairs of bonded atoms
• Can molecules contain multiple different elements?

  Yes, they can
• What is an example of a molecule that contains multiple different elements?

  Water (H2O)
• What is a compound?

  A substance with two or more different elements
• Why is water considered a compound?

  It contains hydrogen and oxygen
• What is the formula for carbon dioxide?

  CO2
• What is a key feature of compounds regarding the elements involved?

  They are always in the same proportions
• How would you write the formula for water?

  H2O
• What does the subscript in a chemical formula signify?

  The number of atoms of that element
• What is the formula for sulfuric acid?

  H2SO4
• How can you identify the number of atoms in a compound's formula?

  By reading the chemical symbols and subscripts
• What do brackets in chemical formulas indicate?

  Grouping of atoms with a multiplier
• What is the formula for calcium hydroxide?

  Ca(OH)2
• How do ionic bonds affect the structure of compounds?

  They form large structures, not molecules
• What is the formula for table salt?

  NaCl
• What does the formula NaCl represent in terms of sodium and chloride?

  They are in a one-to-one ratio
• What is a mixture?

  Two or more substances not chemically combined
• How can you separate substances in a mixture?

  Using physical methods like filtration
• What is an example of a physical method for separating mixtures?

  Filtration
• What are the differences between molecules, compounds, and mixtures?

  • Molecules: Groups of two or more atoms.
  • Compounds: Substances with two or more different elements.
  • Mixtures: Two or more substances not chemically combined.
• How do ionic bonds influence the structure of compounds compared to covalent bonds?

  • Ionic bonds: Form large structures, not individual molecules.
  • Covalent bonds: Form distinct molecules with specific ratios.
• What are the key features of chemical formulas for compounds?

  • Indicate the elements present.
  • Show the number of each atom.
  • Use subscripts for quantities.
  • May include brackets for grouping.