(Chemical Equations & Chemical Reactions) Conservation of Mass (Chemical Equations & Chemical Reactions) HS-PS1-7 Level 1

Chemical Reaction → when the bonds between atoms of a substance are broken and the atoms rearrange and form new bonds to make substances.

How do you know when a chemical reaction occurs? What is your evidence? Temperature change Color Change (not color intensity) Light

Appearance of a solid (precipitate) Gas formation Formation of

uses symbols and formulas to show what happens in a chemical reaction Chemical Equation  → uses symbols and formulas to show what happens in a chemical reaction H2O(l) + NaHCO3(s) → NaOH(aq) + CO2(g) + H2O(l)

H2O(l) + NaHCO3(s) → NaOH(aq) + CO2(g) + H2O(l) Reading a Chemical Equation…. ** the arrow is read as “yields” or “produces”** H2O(l) + NaHCO3(s) → NaOH(aq) + CO2(g) + H2O(l) water plus sodium bicarbonate yields sodium hydroxide plus carbon dioxide plus water

Product(s) Reactant(s) Parts of a Chemical Equation H2O(l) + NaHCO3(s) → NaOH(aq) + CO2(g) + H2O(l) Product(s) Reactant(s) *what is used in a reaction *always BEFORE the arrow *what is produced/made during a reaction * Always AFTER the arrow

phase notations l = liquid H2O(l) + NaHCO3(s) → NaOH(aq) + CO2(g) + H2O(l) phase notations l = liquid s = solid aq = aqueous (dissolved in water) g = gas

coefficient 2H2(g) + O2(g) → 2H2O(l) * number before the formula of a compound or single element * how many you have of a compound * no number = 1 coefficient

closed system = sealed environment Conservation of Mass In a closed system, the total mass of the products from a chemical reaction will equal the total mass of the reactants; mass is CONSERVED closed system = sealed environment