Question

section 2 september 16 - september 26
day 1
in your words, explain the law of conservation of matter.
day 2
when balancing a chemical equation, what do you call the large number in front of the chemical symbol?
ch₄ + 2o₂ → co₂ + 2h₂o
day 3
when balancing a chemical equation, what do you call the small number behind a symbol?
day 4
illustrate the phase changes and tell what is happening at each stage.
day 5
illustrate how the following combine by showing the electron - configuration and the chemical formula.
na + f
c + o
h + o

Explanation:

• Day 1: The Law of Conservation of Matter states that matter cannot be created or destroyed in a chemical reaction. The total mass of the reactants equals the total mass of the products.
• Day 2: The large number in front of a chemical symbol in a balanced chemical - equation is called a coefficient. It represents the number of moles or molecules of the substance.
• Day 3: The small number behind a symbol in a chemical formula is called a subscript. It indicates the number of atoms of that element in a molecule.
• Day 4: Phase changes include melting (solid to liquid), freezing (liquid to solid), vaporization (liquid to gas), condensation (gas to liquid), sublimation (solid to gas), and deposition (gas to solid). During melting, heat is absorbed and the substance changes from a solid to a liquid state as the intermolecular forces are weakened.
• Day 5:
• For Na + F: Sodium (Na) has an electron configuration of 1s²2s²2p⁶3s¹ and fluorine (F) has 1s²2s²2p⁵. Na loses one electron to form Na⁺ and F gains one electron to form F⁻. The chemical formula is NaF.
• For C + O: Carbon (C) has an electron configuration of 1s²2s²2p² and oxygen (O) has 1s²2s²2p⁴. In carbon - dioxide formation, carbon shares electrons with oxygen. The chemical formula is CO₂.
• For H + O: Hydrogen (H) has an electron configuration of 1s¹ and oxygen (O) has 1s²2s²2p⁴. In water formation, two hydrogen atoms share electrons with one oxygen atom. The chemical formula is H₂O.

Answer:

• Day 1: The Law of Conservation of Matter means matter is conserved in chemical reactions; total mass of reactants = total mass of products.
• Day 2: Coefficient.
• Day 3: Subscript.
• Day 4: Phase changes include melting (solid - liquid, heat absorption weakens intermolecular forces), freezing, vaporization, condensation, sublimation, and deposition.
• Day 5: Na + F forms NaF; C + O forms CO₂; H + O forms H₂O.