Title: Chemical Equations
1Chemical Equations
- synthesis
- decomposition
- combustion of a hydrocarbon
- single replacement
- double replacement
2Parts of a chemical equation
3Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
4Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
5Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
6Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
7Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
8Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
s solid insoluble precipitate
9Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
s solid insoluble precipitate aq aqueous
solution dissolved in water
10Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
s solid insoluble precipitate aq aqueous
solution dissolved in water g gas l
liquid
11Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
12Parts of a chemical equation
- Mg(s) 2 HCl(aq) ? H2(g) MgCl2(aq)
13In a chemical reaction, existing atoms are simply
rearranged. The atoms on both sides of the
equation must balance.
- N2 H2 ? NH3 (not balanced)
14In a chemical reaction, existing atoms are simply
rearranged. The atoms on both sides of the
equation must balance.
- N2 3 H2 ? 2 NH3 (balanced)
15Tips for balancing reactions.
- Start by balancing elements that are only found
once on each side of the reaction. - Example CO2 H2 ? C2H6 H2O
16Tips for balancing reactions.
- Start by balancing elements that are only found
once on each side of the reaction. - Example CO2 H2 ? C2H6 H2O
- Balance the carbons and oxygens first.
17Tips for balancing reactions.
- Start by balancing elements that are only found
once on each side of the reaction. - Example 2 CO2 H2 ? C2H6 4 H2O
- Balance the carbons and oxygens first.
18Tips for balancing reactions.
- Start by balancing elements that are only found
once on each side of the reaction. - Example 2 CO2 7 H2 ? C2H6 4 H2O
- Finally, balance the hydrogens.
19Tips for balancing reactions.
- Start by balancing elements that are only found
once on each side of the reaction. - When the same polyatomic ion is present on both
sides of an equation, balance the entire ion
rather than the individual elements. - Example CaCl2 AgNO3 ? Ca(NO3)2 AgCl
20Tips for balancing reactions.
- Start by balancing elements that are only found
once on each side of the reaction. - When the same polyatomic ion is present on both
sides of an equation, balance the entire ion
rather than the individual elements. - Example CaCl2 2 AgNO3 ? Ca(NO3)2 AgCl
- The nitrate ions can be balanced as if they are a
single element.
21Tips for balancing reactions.
- Start by balancing elements that are only found
once on each side of the reaction. - When the same polyatomic ion is present on both
sides of an equation, balance the entire ion
rather than the individual elements. - Example CaCl2 2 AgNO3 ? Ca(NO3)2 2 AgCl
- Balance the Ca, Cl, and Ag to complete.
22Tips for balancing reactions.
- Start by balancing elements that are only found
once on each side of the reaction. - When the same polyatomic ion is present on both
sides of an equation, balance the entire ion
rather than the individual elements. - If you have an element that is even on one side
and odd on the other, place a coefficient of 2 in
front of the substance on the odd side.
233. If you have an element that is even on one
side and odd on the other, place a coefficient of
2 in front of the substance on the odd side.
- KClO3 ? KCl O2
- There are 3 oxygen atoms on the left and 2 on the
right.
24If you have an element that is even on one side
and odd on the other, place a coefficient of 2 in
front of the substance on the odd side.
- 2KClO3 ? KCl O2
- Place a coefficient of 2 in front of the KClO3.
25If you have an element that is even on one side
and odd on the other, place a coefficient of 2 in
front of the substance on the odd side.
- 2KClO3 ? 2KCl 3O2
- Now balance the equation.
26Synthesis Reactions (A B ? AB)
- Two or more substances combine to form a larger
compound.
27Synthesis Reactions (A B ? AB)
- Two or more substances combine to form a larger
compound. - Example 2 H2(g) O2(g) ? 2 H2O(l)
28Synthesis Reactions (A B ? AB)
- Two or more substances combine to form a larger
compound. - Example 2 H2(g) O2(g) ? 2 H2O(l)
- Example MgO(s) CO2(g) ? MgCO3(s)
29Decomposition (AB ? A B)
- A single compound breaks down into two or more
smaller substances.
30Decomposition (AB ? A B)
- A single compound breaks down into two or more
smaller substances. - Example 2 NaHCO3(s) ? CO2(g) H2O(g)
Na2CO3(s)
31Combustion of a hydrocarbon(CxHyOz O2 ? CO2
H2O)
- Any hydrocarbon that burns in the presence of
oxygen will produce carbon dioxide and water
vapor.
32Combustion of a hydrocarbon(CxHyOz O2 ? CO2
H2O)
- Any hydrocarbon that burns in the presence of
oxygen will produce carbon dioxide and water
vapor. - Balance by giving the hydrocarbon a coefficient
of 2, then balance C, H, and then O. Check to
see if the coefficients can be simplified.
33Combustion of a hydrocarbon(CxHYOz O2 ? CO2
H2O)
- Any hydrocarbon that burns in the presence of
oxygen will produce carbon dioxide and water
vapor. - Balance by giving the hydrocarbon a coefficient
of 2, then balance C, H, and then O. Check to
see if the coefficients can be simplified. - Example C3H8(g) O2(g) ? CO2(g) H2O(g)
34Example 2C3H8(g) O2(g) ? CO2(g) H2O(g)
- Start by giving the hydrocarbon a coefficient of
2.
35Example 2C3H8(g) O2(g) ? 6CO2(g) H2O(g)
- Start by giving the hydrocarbon a coefficient of
2. - Now balance the carbons.
36Example 2C3H8(g) O2(g) ? 6CO2(g) 8H2O(g)
- Start by giving the hydrocarbon a coefficient of
2. - Now balance the carbons.
- Balance the hydrogens.
37Example 2C3H8(g) 10O2(g) ? 6CO2(g) 8H2O(g)
- Start by giving the hydrocarbon a coefficient of
2. - Now balance the carbons.
- Balance the hydrogens.
- Balance the oxygens (be sure to count all of
them.)
38Example C3H8(g) 5O2(g) ? 3CO2(g) 4H2O(g)
- Start by giving the hydrocarbon a coefficient of
2. - Now balance the carbons.
- Balance the hydrogens.
- Balance the oxygens (be sure to count all of
them.) - Finally, if all the coefficients are even, divide
them all by 2.
39Chemical Equations
- synthesis
- decomposition
- combustion of a hydrocarbon
- single replacement
- double replacement
40Single Replacement (A BC ? B AC)
- A pure element replaces a similar element in a
compound.
41Single Replacement (A BC ? B AC)
- A pure element replaces a similar element in a
compound. - Metals replace the positive ion, nonmetals
replace the negative ion.
42Single Replacement (A BC ? B AC)
- A pure element replaces a similar element in a
compound. - Metals replace the positive ion, nonmetals
replace the negative ion. - Example Ca(s) AlCl3(aq) ?
43Single Replacement (A BC ? B AC)
- A pure element replaces a similar element in a
compound. - Metals replace the positive ion, nonmetals
replace the negative ion. - Example Ca(s) AlCl3(aq) ? Al(s) CaCl2(aq)
44Single Replacement (A BC ? B AC)
- A pure element replaces a similar element in a
compound. - Metals replace the positive ion, nonmetals
replace the negative ion. - Example 3 Ca(s) 2 AlCl3(aq) ? 2 Al(s) 3
CaCl2(aq)
45Single Replacement (A BC ? B AC)
- A pure element replaces a similar element in a
compound. - Metals replace the positive ion, nonmetals
replace the negative ion. - Example 3 Ca(s) 2 AlCl3(aq) ? 2 Al(s) 3
CaCl2(aq) - Example F2(g) SrBr2(aq) ?
46Single Replacement (A BC ? B AC)
- A pure element replaces a similar element in a
compound. - Metals replace the positive ion, nonmetals
replace the negative ion. - Example 3 Ca(s) 2 AlCl3(aq) ? 2 Al(s) 3
CaCl2(aq) - Example F2(g) SrBr2(aq) ? Br2(l) SrF2(aq)
47Single Replacement (A BC ? B AC)
- A pure element replaces a similar element in a
compound. - Metals replace the positive ion, nonmetals
replace the negative ion. - Example 3 Ca(s) 2 AlCl3(aq) ? 2 Al(s) 3
CaCl2(aq) - Example F2(g) SrBr2(aq) ? Br2(l) SrF2(aq)
- H, O, N, Cl, Br, I, F form diatomic molecules in
their pure form and require a subscript of 2
48Chemical Equations
- synthesis
- decomposition
- combustion of a hydrocarbon
- single replacement
- double replacement
49Double Replacement (AB CD ? AD CB)
- Two elements in compounds switch places. One of
the two products will be a solid precipitate
(insoluble compound).
50Double Replacement (AB CD ? AD CB)
- Two elements in compounds switch places. One of
the two products will be a solid precipitate
(insoluble compound). - It is important to include states of matter (s,
l, g, aq) when writing these equations.
51Double Replacement (AB CD ? AD CB)
- Two elements in compounds switch places. One of
the two products will be a solid precipitate
(insoluble compound). - It is important to include states of matter (s,
l, g, aq) when writing these equations. - One product will be a solid, called a
precipitate. It will be the product with the
greatest charges and no nitrate ions, NO3-.
52sodium chloride silver nitrate ? ?
53sodium chloride silver nitrate ? ?
- The reactants in a double replacement reaction
will always be aqueous.
54sodium chloride silver nitrate ? ?
- The reactants in a double replacement reaction
will always be aqueous. - NaCl(aq) AgNO3(aq) ?
55sodium chloride silver nitrate ? ?
- The reactants in a double replacement reaction
will always be aqueous. - Switching the metals will give you the correct
partners for the products. - NaCl(aq) AgNO3(aq) ?
56sodium chloride silver nitrate ? ?
- The reactants in a double replacement reaction
will always be aqueous. - Switching the metals will give you the correct
partners for the products. - NaCl(aq) AgNO3(aq) ? AgCl( ) NaNO3( )
57sodium chloride silver nitrate ? ?
- The reactants in a double replacement reaction
will always be aqueous. - Switching the metals will give you the correct
partners for the products. - The AgCl is the solid, since the other product
has a nitrate ion. - NaCl(aq) AgNO3(aq) ? AgCl(s) NaNO3(aq)
58lithium carbonate calcium bromide ? ?
59lithium carbonate calcium bromide ? ?
- Reactants must be aqueous.
- Li2CO3(aq) CaBr2(aq) ?
60lithium carbonate calcium bromide ? ?
- Reactants must be aqueous.
- Switch the metals to obtain new compounds.
- Li2CO3(aq) CaBr2(aq) ? CaCO3( ) LiBr( )
61lithium carbonate calcium bromide ? ?
- Reactants must be aqueous.
- Switch the metals to obtain new compounds.
- Calcium carbonate is the solid, because it has
charges of 2 and 2-, as opposed to lithium
bromide, which has charges of 1 and 1-. - Li2CO3(aq) CaBr2(aq) ? CaCO3(s) LiBr(aq)
62lithium carbonate calcium bromide ? ?
- Reactants must be aqueous.
- Switch the metals to obtain new compounds.
- Calcium carbonate is the solid, because it has
charges of 2 and 2-, as opposed to lithium
bromide, which has charges of 1 and 1-. - Balance the equation.
- Li2CO3(aq) CaBr2(aq) ? CaCO3(s) 2 LiBr(aq)