Unit 2: Chemistry

Science 10

Name: Block:

Book 4: Types of

Chemical Reactions

Classifying Chemical Reactions

• There are many types/classes of chemical reactions

• Classifying helps find out how chemical reactions work and allows us to___________________________________

• By understanding how one chemical reaction works, scientists canunderstand more about how other reactions between ______________________________________ will behave

Chemical reactions can be classified as:

1. ___________________________________

2. ___________________________________

3. ___________________________________

4. ___________________________________

5. ___________________________________

• Reactions with common reactants would be in the same “_____________________” of reaction

• One way to predict the outcome of a specific reaction is by recognizing that chemical reactions follow___________________.

• Every kind of chemical reaction involves a unique combination of substances. Reactant bonds ____________,atoms rearrange, and ________ products are formed.

• There are many patterns in the way substances react which allow Chemists to classify chemical reactions in orderto predict the products.

1. Synthesis Reactions (also called combination reactions)In a synthesis reaction, two or more reactants (A and B) combine to produce a single product (AB).

• two or more elements form ______________________• or ______________________ combine to form one product

Examples:2Mg(s) + O2(g)

2Na(s) + Cl2(g)

SO3(g) + H2O(l)

Where do we see synthesis reactions…?

___________________(large chemical plants)

• Create hydrochloric acid for laboratories

Environment

• Metals exposed to air react with ___________________ (rust)

Burning (___________________)

• Coal reacts with oxygen when burning

___________________________

• Plants and animals take simple substances (water, nitrogen, CO2,and oxygen) to produce larger complex molecules (sugar,carbohydrates, proteins)

Example 1: To make table salt in a synthesis reaction, two atoms of sodium metal (Na) and one molecule of chlorine gas (Cl2) react to form sodium chloride, NaCl

Balanced chemical equation:

_____________ + ______________ _______________

REMEMBER: that chlorine is written as a diatomic molecule, Cl2. Chlorine occurs as a diatomic molecule when it is a pure element. You need to remember your “HOFBrINCl” elements: H2, N2, O2, F2, Cl2, Br2, and I2. When diatomic elements are not combined into a compound, they exist as molecules containing two atoms.

Synthesis Reaction: EXAMPLES

Example 2 2Mg(s) + O2(g) ___________

Evidence of a Chemical Reaction?Think of the comments in the video…

What evidence was there a chemical reaction took place? _____________CHANGE (light produced)

ENERGY CHANGE (heat produced…temperatures exceeding 400°C)

____________PRODUCT (MgO powder remains)

____________FORMATION (some Mg3N2 is produced which reacts to produce ammonium gas)

Magnesium burns and produces a dangerously bright white light (can severely damage eyes).

Predicting Products:Synthesis of a ___________+ __________________produces an ionic compound.

Reactants are ions, so “swap and drop” to find the chemical formula of the product:

Synthesis of 2 ___________________produces a covalent compound.

The formulas are much more difficult to predict at our level, so you will always be given more info….like a WORD EQUATION!

Assignment #1: Questions #1-2 textbook page 259 Complete this assignment on a separate page

2. Decomposition ReactionIn a decomposition reaction, is the _____________________________of a compound into smaller compounds or separate __________________. A decomposition reaction is the reverse of a synthesis reaction.

EXAMPLES:

Decomposition of a Covalent Compound

In all decomposition reactions there is 1 ______________________and several product substances.

FOR EXAMPLE When an electric current is passed through water, it decomposes into hydrogen and oxygen gas.

Name _____________________________________________________________________________ Period __________

Types of Reactions Worksheet

Given the reactions below, identify each as synthesis (S), decomposition (D), single replacement

(SR), double replacement (DR), or combustion (C). Afterwards, balance the reaction.

1) ____ K + ____ Cl2 ____ KCl Type of Reaction: ____________

2) ____ NH3 ____ N2 + ____ H2 Type of Reaction: ____________

3) ____ NaF + ____ Br2 ____ NaBr + ____ F2 Type of Reaction: ____________

4) ____ SO2 + ____ Li2Se ____ SSe2 + ____ Li2O Type of Reaction: ____________

5) ____PbSO4 ____ PbSO3 + ____ O2 Type of Reaction: ____________

6) Al + _ _ Fe2O3 Fe + _ _ Al2O3 Type of Reaction: ____________

7) _ _ SF6 __ S + F2 Type of Reaction: ____________

8) _ _ C2H4 + O2 CO2 + H2O Type of Reaction: ____________

9) ____ KClO3 ____ KCl + O2 Type of Reaction: ____________

10) Pb(NO3)2 + NaCl NaNO3 + PbCl2 Type of Reaction: ____________

11) What type of reaction is shown to the left?

12) Using the key provided, write the complete chemical formula shown in the box above:

_______________ + ______________ _______________

13) Now balance the equation above so that both sides of the reaction are equal.

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Six Types of Chemical Reaction WorksheetBalance the following reactions and indicate which of the six types of chemicalreaction are being represented:

1) ____ NaBr + ____ Ca(OH)2 ___ CaBr2 + ____ NaOH

Type of reaction: _____________________________

2) ____ NH3+ ____ H2SO4 ____ (NH4)2SO4

Type of reaction: _____________________________

3) ____ C5H9O + ____ O2 ____ CO2 + ____ H2O

Type of reaction: _____________________________

4) ____ Pb + ____ H3PO4 ____ H2 + ____ Pb3(PO4)2

Type of reaction: _____________________________

5) ____ Li3N + ____ NH4NO3 ___ LiNO3 + ___ (NH4)3N

Type of reaction: _____________________________

6) ____ HBr + ___ Al(OH)3 ___ H2O + ___ AlBr3

Type of reaction: _____________________________

7) What’s the main difference between a double displacement reaction andan acid-base reaction?

8) Combustion reactions always result in the formation of water. What othertypes of chemical reaction may result in the formation of water? Writeexamples of these reactions on the opposite side of this paper.

For chemistry help, visit www.chemfiesta.com © 2001 Cavalcade Publishing All Rights Reserved

Six Types of Chemical Reaction WorksheetAnswers

Balance the following reactions and indicate which of the six types of chemicalreaction are being represented:

1) 2 NaBr + 1 Ca(OH)2 1 CaBr2 + 2 NaOHType of reaction: double displacement

2) 2 NH3+ 1 H2SO4 1 (NH4)2SO4Type of reaction: synthesis

3) 4 C5H9O + 27 O2 20 CO2 + 18 H2OType of reaction: combustion

4) 3 Pb + 2 H3PO4 3 H2 + 1 Pb3(PO4)2Type of reaction: single displacement

5) 1 Li3N + 3 NH4NO3 3 LiNO3 + 1 (NH4)3NType of reaction: double displacement

6) 3 HBr + 1 Al(OH)3 3 H2O + 1 AlBr3Type of reaction: acid-base

7) What’s the main difference between a double displacement reaction andan acid-base reaction?Acid-base reactions form water.

8) Combustion reactions always result in the formation of water. What othertypes of chemical reaction may result in the formation of water? Writeexamples of these reactions on the opposite side of this paper.Acid-base: HCl + NaOH H2O + NaClSynthesis: 2 H2 + O2 2 H2ODecomposition: NH4OH NH3 + H2OSingle displacement: H2 + 2 NaOH 2 Na + 2 H2O (not common)