3.1 Chemical measurements, conservation of mass, and the quantitative interpretation of chemical equations

• What are chemical measurements used for in chemistry?

  Determining composition, purity, behavior
• If 12g of carbon reacts with 32g of oxygen, the total mass of carbon dioxide produced is 44g.


  True
• Steps to balance a chemical equation:

  1️⃣ Write the unbalanced equation

  2️⃣ Count atoms

  3️⃣ Balance elements

  4️⃣ Check the balance

  5️⃣ Simplify coefficients
• What law ensures that balancing chemical equations is necessary?

  Law of conservation of mass
• To calculate molar mass, the atomic mass of each element is multiplied by the number of atoms in the formula
• What are chemical measurements used for in chemistry?

  Composition, purity, behavior
• In the combustion of methane, the total mass of reactants equals the total mass of products.


  True
• How is the molar mass of a substance calculated?

  Sum of atomic masses
• Steps to perform stoichiometric calculations

  1️⃣ Write the balanced chemical equation

  2️⃣ Identify the known and unknown quantities

  3️⃣ Convert to moles

  4️⃣ Apply mole ratio

  5️⃣ Convert back to desired units
• The law of conservation of mass states that matter cannot be created or destroyed
• Match the chemical property with its measurement type:

  Composition ↔️ Spectroscopic analysis

  Purity ↔️ Chromatography

  Concentration ↔️ Titration

  Temperature ↔️ Thermometry
• To balance the oxygen in the equation H₂ + O₂ → H₂O, a coefficient of 2 is added to H₂O
• The molar mass of a substance is measured in grams per mole (g/mol).


  True
• Match the reactant or product with its molar mass in g/mol:

  H₂ ↔️ 2.016

  O₂ ↔️ 32.00

  H₂O ↔️ 18.016
• The law of conservation of mass states that matter cannot be created or destroyed
• The molar mass of a substance is measured in grams per mole
• In the reaction 2H₂ + O₂ → 2H₂O, the mole ratio of H₂ to O₂ is 2:1.


  True