Describing Chemical Reactions

Try These

Q1. Balance these skeleton equations.
___ H2 + ___ Cl2  ___ HCl Elements Reactants Products	___ Fe +___ O2  ___ Fe2 O3 Elements Reactants Products

Questions

Balance the following skeleton equations. Use the coefficient “1” instead of leaving the blanks empty.

Q1. ___ _­ Fe + ___ Cl₂  ___ FeCl₃
Q2. ___ NOCl  ___ NO + ___ Cl₂
Q3. ___ N₂ + ___ O₂  ___ N₂O₅
Q4. ___ Cs + ___ N₂  ___ Cs₃N
Q5. ___ HCl + ___ AgNO₃  ___ HNO₃ + ___ AgCl
Q6. ___ H₂SO₄ + ___ B(OH)₃  ___ B₂(SO₄)₃ + ___ H₂O
Q7. ___ Al + ___ S₈  ___ Al₂S₃
Q8. ___ C₂H₄ + ___ O₂  ___ CO₂ + ___ H₂O
Q9. ___ NaOH + ___ H₂CO₃  ___ Na₂CO₃ + ___ H₂O
Q10. ___ Al + ___ O₂  ___ Al₂O­₃
Q11. ___ BN + ___ IF  ___ NI₃ + ___ BF₃
Q12. ___ Cu + ___ H₂SO₄  ___ CuSO₄ + ___ SO₂ + ___ H₂O
Q13. ___ NaHCO₃  ___ Na₂CO₃ + ___ CO₂ + ___ H₂O
Q14. ___ P₄ + ___ O₂  ___ P₄O₁₀
Q15. ___ C₆H₆ + ___ O₂  ___ CO₂ + ___ H₂O

	What do you call a nosy pepper?
	Date:	Name:

The following chemical equations are incorrectly balanced. Each equation has only one error. Circle the error and correct it by placing the correct coefficient. The letter below the incorrect coefficient matches with the question number at the bottom of the page.

The first question has been done for you.

1. 2 1­ Cu + 1 O2  2 CuO I E O	2. 1­ N2 + 2 H2  2 NH3 B L M
3. 4­ Sb + 2 O2  1 Sb4O6 A U Y	4. 4­ H2SiCl2 + 4 H2O  1 H8Si4O4 + 4 HCl C P W B
5. 1­ P4O10 + 4 H2O  4 H3PO4 E O R	6. 1­ Ca3P2 + 6 H2O  3 Ca(OH)2 + 3 PH3 F G L P
7. 2­ NiS + 2 O2  2 NiO + 2 SO2 J E S D	8. 1­ POCl3 + 3 H2O  2 H3PO4 + 3 HCl R Z S A
9. 2­ Ca5F(PO4)3 + 7 H2SO4  5 Ca(H2PO4)2 + 7 CaSO4 + 2 HF D K N L O
10. 3­ K2MnO4 + 2 H2SO4  2 KMnO4 + 2 MnO2 + 2 K2SO4 + 2 H2O T G P J O I
11. 2­ HCl + 1 CaCO3  1 CaCl2 + 1 CO2 + 2 H2O H V E M A

												I
10	11	2	11	6	7	9	5		4	3	8	1	9	7	8	8

	Balancing Combustion Reactions – Extra Practice
	Date:	Name:

Q1. ___ C₃H₈ + ___ O₂  ___H₂O + ___ CO₂

Q2. ___ CH₄ + ___ O₂  ___H₂O + ___ CO₂

Q3. ___ C₅H₁₂ + ___ O₂  ___H₂O + ___ CO₂

Q4. ___ C₇H₆O₃ + ___ O₂  ___H₂O + ___ CO₂

Q5. ___ C₁₅H₃₀ + ___ O₂  ___H₂O + ___ CO₂

Q6. ___ C₁₂H₂₆ + ___ O₂  ___H₂O + ___ CO₂

Q7. ___ C₄H₁₀ + ___ O₂  ___H₂O + ___ CO₂

Q8. ___ C₁₂H₂₂O₁₁ + ___ O₂  ___H₂O + ___ CO₂

Q9. ___ C₆H₁₄ + ___ O₂  ___H₂O + ___ CO₂

Q10. Challenge:

Come up with a general rule using the variable “n” for the combustion of C_nH_2n+2

___ C_nH_2n+2 + ___ O₂  ___H₂O + ___ CO₂
Test your rule against
___ C₈H₁₈ + ___ O₂  ___H₂O + ___ CO₂

___ C₁₆H₃₄ + ___ O₂  ___H₂O + ___ CO₂

	Types of Chemical Reactions
	Date:	Name:

Chemists classify chemical reactions in order to organize many reactions that occur daily in living things, laboratories and industry. Most chemical reactions can be classified into one of the five categories.

Combustion

A combustion reaction is when _______________ combines with a substance and releases energy in the form of _______________ and _______________. An example of this kind of reaction involves methane gas and oxygen. Methane is major component of natural gas.

CH₄ + 2 O₂  CO₂ + 2 H₂O

^{methane oxygen carbon dioxide water}

Similarly propane gas (used to fuel barbeque grills) yields the same product when burnt with oxygen.

C₃H₈ + 5 O₂  3 CO₂ + 4 H₂O

^{propane oxygen carbon dioxide water}

In ___________________ combustion, the products are carbon dioxide and water with energy given off. With too little oxygen present ________________________________ can occur. There are two additional products in an incomplete combustion reaction: carbon (soot) and the dangerous carbon monoxide gas.

C₄H₁₀ + 5O₂  2 CO₂ + 5 H₂O + CO + C

^{butane oxygen carbon dioxide water carbon monoxide carbon}

Combustion Clue: ______________________________________________________________________________________________________________________________________________

Synthesis

A synthesis (combination) reaction is when two or more reactants combine to produce a _______________ product. In general, synthesis reactions look like:

A + B  AB
One example of a synthesis reaction is the combination of iron and sulfur to form iron (II) sulfide.

8 Fe + S₈  8 FeS

^{iron sulfur iron(II) sulfide}

Synthesis Clue:

_______________________________________________________________________

_______________________________________________________________________
Decomposition

A decomposition (splitting apart) reaction is the opposite of a synthesis reaction – a single compound breaks down into _______________ elements or new compounds. A decomposition reaction often requires an energy source, such as _______________, _______________, or ____________________, to occur. In generic terms, decomposition reactions look like the following:

AB  A + B
One example of a decomposition reaction is the electrolysis of water to make oxygen and hydrogen gas. An electric current is passed through to break water molecules into hydrogen and oxygen.

2 H₂O  2 H₂ + O₂

^{water hydrogen gas oxygen gas}

Another example of decomposition reaction is an air bag. Automobile air bags inflate rapidly as sodium azide pellets decompose. A device that can provide an electric signal to start the reaction is packaged inside air bags along with sodium azide pellets.

2NaN₃  2Na + 3N₂

^{sodium azide sodium nitrogen gas}
Decomposition Clue:

_______________________________________________________________________

_______________________________________________________________________

Single Replacement

This is when one element _______________ with another element in a compound. In generic terms, single replacement reactions look like the following.

A + BC  AC + B
One example of a single replacement reaction is when carbon replaces nickel in nickel oxide to produce pure nickel and carbon monoxide:
C + NiO  Ni + CO

^{carbon nickel (II) oxide nickel carbon monoxide}
Single Replacement Clue:

______________________________________________________________________________________________________________________________________________

Double Replacement

This is when the _______________ and _______________ of two different compounds switch places, forming two entirely different compounds. In generic terms, double replacement reactions look like the following.

AX + BY  AY + BX
In this generic reaction A and B represent positively charged ions (cations) and X and Y represent negatively charged ions (anions). All double replacement reactions produce either a _______________, a _______________, or _______________.
One example of a double replacement reaction is the reaction of sodium hydroxide with copper (II) chloride to form sodium chloride and copper (II) hydroxide. A salt and a precipitate are produced.
2NaOH + CuCl₂  2NaCl + Cu(OH)₂

^{sodium hydroxide copper (II) chloride sodium chloride copper (II) hydroxide}
In the following double-replacement reaction a salt and water is produced.
HBr + NaOH  NaBr + H₂O

^{hydrobromic acid sodium hydroxide sodium bromide water}
Double Replacement Clue:

______________________________________________________________________________________________________________________________________________

Type of Reaction	A School Dance Analogy
Combustion
Synthesis
Decomposition
Single Replacement
Double Replacement

	What is the Definition of a Good Farmer?
	Date:	Name:

For each of the following chemical reactions, determine the type of reaction and circle the corresponding letter. Write the letter at the bottom of the page above the corresponding question.

	Combustion	Synthesis	Decomposition	Single Replacement	Double Replacement
Q1. CaSO4 + Mg(OH)2  Ca(OH)2 + MgSO4	U	A	Q	E	L
Q2. CH4 + 2 O2  CO2 + 2 H2O	E	R	N	L	F
Q3. 2 Fe + 6 NaBr  2 FeBr3 + 6 Na	B	K	I	S	D
Q4. CaSO4 + Mg(OH)2  Ca(OH)2 + MgSO4	D	F	Y	M	H
Q5. 2 KClO3  3KCl + 3 O2	I	O	G	C	W
Q6. NaOH + KNO3  NaNO3 + KOH	G	S	C	R	I
Q7. Pb + O2  PbO2	P	D	M	X	E
Q8. Na2CO3  Na2O + CO2	H	G	F	I	B
Q9. NH4OH + HBr  H2O + NH4Br	J	E	L	T	N
Q10. P4 + 5O2  2 P2O5	A	U	W	G	M
Q11. Zn + 2 HCl  ZnCl2 + H2	K	V	N	O	P
Q12. H2O  H2 + O2	S	J	T	E	A
Q13. Zn + S  ZnS	U	M	L	Q	V
Q14. C3H8 + 5 O2  3 CO2 + 4 H2O	A	T	O	Z	H

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		6	9		4	6	3		8	6	2	1	7

© 2014 Michelle Brosseau, Mrs. Brosseau’s Binder