Download Chapter 6 Notes - Discount Flies

Chapter 6 - Chemical Reactions
Evidence for a chemical reaction is sometimes visual, and can include any
or all of the following:
1) Color Change
2) Solid Forms
3) Gas Given Off
4) Heat, Cold or Flames
To represent a chemical reaction, we write a chemical equation
CH4 + O2
→
CO2 + H2O
Reactants
where → is read as: yields or produces or gives off
Products
To add more information about a reaction:
(s)
solid
(l)
liquid
(g)
gas
(aq)
aqueous (dissolved in water)
CH4(g) + O2(g)
→
CO2(g) + H2O(g)
Write an equation:
Solid Mercury (II) oxide becomes liquid mercury and gaseous oxygen
Solid zinc is added to aqueous
hydrochloric acid to form aqueous zinc
chloride and hydrogen gas.
Ammonia gas reacts with oxygen gas to produce gaseous nitrogen monoxide
and gaseous water.
Solid sodium bicarbonate is changed into solid sodium carbonate, gaseous
water and gaseous carbon dioxide.
Aqueous chromium (II) nitrate added to aqueous sodium phosphate makes
aqueous sodium nitrate and solid chromium (II) phosphate.
CH4(g) + O2(g)
→
CO2(g) + H2O(g)
2 oxygen atoms become 3 oxygen atoms, and 4 hydrogen atoms become
2???
Coeffecient = a whole number written in front of a
substance which indicates the number of molecules
that react.
Tricks for balancing:
1. Write correct formulas for reactants and
products first. Don’t ever change the formula of a
substance once it is written correctly.
2. Balance O and H last.
Write an equation, then balance:
Solid Mercury (II) oxide becomes liquid mercury and gaseous oxygen
Solid zinc is added to aqueous
hydrochloric acid to form aqueous zinc
chloride and hydrogen gas.
Ammonia gas reacts with oxygen gas to produce gaseous nitrogen monoxide
and gaseous water.
Solid sodium bicarbonate is changed into solid sodium carbonate, gaseous
water and gaseous carbon dioxide.
Aqueous chromium (II) nitrate added to aqueous sodium phosphate makes
aqueous sodium nitrate and solid chromium (II) phosphate.