Balancing and Identifying Chemical Reactions: A Review

Balancing and Identifying Chemical Reactions: A Review

We are going to review the steps of balancing chemical reactions, and learn how to identify the reactions.

Multiple Choice

What does the Law of Conservation of Mass state?

• Matter cannot be gained or lost in a chemical reaction.
• Matter can only be lost in a chemical reaction.
• Matter can only be gained in a chemical reaction.
• Matter can be gained and lost in a chemical reaction. 

Multiple Choice

If reaction starts with 20g of reactants it should produce 

• a total of 40g of products
• a total of 10g of products
• a total of 80 g of products
• a total of 20g of products

Multiple Choice

A student mixes 125 grams of sugar, 250 grams of water and 5 grams of flavoring. The solution weighs...

• 250 grams

• 380 grams

• 375 grams

• 400 grams

Multiple Choice

Why must the number of atoms on either side of the arrow be equal to each other in a chemical equation?

• to abide by the law of conservation of energy

• to abide by law of conservation of mass

• to abide by the law of fundamental equations

• because everything must be even for the universe to stay in balance

Multiple Choice

Matter can not be created nor destroyed: it can only be

• Destroyed a little bit

• Invisible

• Transformed, changed

• None of the above

Multiple Choice

What will weigh more when a chemical change is complete?  The reactants before the chemical reaction, or the product after the reaction is complete?

• They both will weigh the same
• The product always weighs more than the reactant
• The reactant will weigh more than the product
• They both will loose mass after the reaction

Multiple Choice

________ are the starting substances in a chemical equation.

• Reactants

• Producer

• Reaction

• Products

Multiple Choice

When balancing equations what does
 -->
mean?

• subscript
• equals
• it is just an arrow
• yield

Multiple Choice

What do we call the chemicals that result from a chemical reaction?

• reactants

• products

• subscripts

• coefficients

Multiple Choice

The number in front of a compound or element is a 

• Subscript
• Coefficient
• Superscript
• Charge

Multiple Choice

The number to the lower side of an element is a 

• Subscript
• Superscript
• Coefficient
• Charge

Multiple Choice

The coefficient in  3H₂O is

• 6
• 2
• 3
• 5

Multiple Choice

MgCl₂ represents a chemical

• Element

• Chemical Formula

• Subscript

• Coefficient

Multiple Choice

How many atoms of Carbon are in the following formula?

3C₂H₆

• 3

• 6

• 9

• 18

Multiple Choice

How many atoms are there TOTAL in:
H₂SO₄

• 6
• 5
• 7
• 3

Multiple Choice

How many total atoms are represented?         4Al₂O₃

• 2
• 8
• 5
• 20

Multiple Choice

A chemical reaction is balanced when

• both sides have the same elements
• Both sides have the same  number of atoms
• Same subscripts
• Same coefficients

Multiple Choice

When balancing a chemical equation, you can only change _________, you can never change _______!

• coefficients, subscripts

• subscripts, coefficients

• formulas, subscripts

• coefficients, formula units

Multiple Choice

What do you change when balancing equations?

• subscript

• coefficient

• Element

Multiple Choice

Balance this reaction: ____ C₅H₁₄ + ____ O₂ ----> ____ CO₂ + ____ H₂O

• 1,8,5,7
• 2,12,5,14
• 3,27,15,24
• 2,17,10,14

Multiple Choice

Balance this reaction: ____ GaF₃ + ____ Cs ---> ____ CsF + ____ Ga

• 1,1,3,1

• 1,2,3,1

• 2,3,3,1

• 1,3,3,1

Multiple Choice

Balancing this reaction: ____ CH₄ + ____ O₂ ---> ____ CO₂ + ____ H₂O

• 2,1,3,1

• 1,2,1,2

• 1,2,2,1

• 2,1,1,2

Multiple Choice

Balance this equation
_Zn+_HCl-->_ZnCl₂ +_H₂

• 1,1,2,1
• 1,1,1,2
• 1,2,1,1
• 2,1,1,1

Multiple Choice

Balance this equation,            Al₂O₃ ---> Al + O₂ 

• Cannot be balanced
• 2Al₂O₃ ---> 2Al + 3O₂ 
• 2Al₂O₃ ---> 4Al + 3O₂ 
• 3Al₂O₃ ---> 2Al + O₂ 

Multiple Choice

_K + _Cl₂ →_KCl

• 2 K + 16 Cl₂ → 8 KCl
• 2 K + 1 Cl₂ → 2 KCl
• 3 K + 4 Cl₂ → 3 KCl
• 1 K + 1 Cl₂ →1 KCl

Multiple Choice

Which of the following is an unbalanced equation?

• CaCO₃ --> CaO + CO₂
• PbO₂ + 2H₂-->2Pb + H₂O
• 2Na+ 2H₂O-->2NaOH + H₂
• CS₂ + 2O₂ --> CO₂ + 2SO₂

Multiple Choice

Balance this equation...

Sb₂S₃ + O₂ --> Sb + SO₂

• It is balanced

• Sb₂S₃ + 3O₂ --> 2Sb + 3SO₂

• Sb₂S₃ + O₂ --> 2Sb + SO₂

• I don't know...Oh well!

Multiple Choice

_AlBr₃ + _K₂SO₄ → _KBr + _Al₂(SO₄)₃

• 6 AlBr₃ + 1 K₂SO₄ → 6 KBr + 1 Al₂(SO₄)₃

• 2 AlBr₃ + 3 K₂SO₄ → 6 KBr + 1 Al₂(SO₄)₃

• 1 AlBr₃ + 1 K₂SO₄ → 2 KBr + 3 Al₂(SO₄)₃

• 2 AlBr₃ + 3 K₂SO₄ → 1 KBr + 2 Al₂(SO₄)₃

Multiple Choice

_P₄+_O₂ → _P₂O₃

• 3 P₄+1 O₂ → 2 P₂O₃

• 1 P₄+1 O₂ → 2 P₂O₃

• 1 P₄+ 3 O₂ → 2 P₂O₃

• 1 P₄+ 2 O₂ → 3 P₂O₃

Multiple Choice

_AgNO₃ + _Cu →_Cu(NO₃)₂ + _Ag

• 2 AgNO₃ + 2 Cu → 3 Cu(NO₃)₂ + 1 Ag
• 2 AgNO₃ + 1 Cu → 1 Cu(NO₃)₂ + 2 Ag
• 1 AgNO₃ + 2 Cu → 2 Cu(NO₃)₂ + 1 Ag
• 3 AgNO₃ + 2 Cu → 3 Cu(NO₃)₂ + 2 Ag

Multiple Choice

What are the coefficients that will balance the skeleton equation below?

__MgS + __O₂ → __MgO + __SO₂

• 3,2,2,3

• 2,3,2,2

• 2,3,2,3

• 3,2,2,1

Multiple Choice

What are the coefficients that will balance the skeleton equation below?

__Fe +__O₂ → __Fe₂O₃

• 3,4,2

• 4, 3, 2

• 2,3,4

• 4,2,3

Multiple Choice

What type of reaction is the following:
 $3CuS\ +2Al\ ->\ Al_2S_3+3Cu$ 

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What type of reaction is the following:
 $2KI\ ->\ 2K\ +\ I_2$  

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What type of reaction is the following:
 $C_{11}H_{24}+17O_2->\ 11CO_2\ +\ 12H_2O$  

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What type of reaction is the following:
 $BaCl_2+2KI\ ->\ 2KCl\ +\ BaI_2$  

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What type of reaction is the following:
 $2H_2+O_2->2H_2O$  

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

Identify the type of chemical reaction

• Synthesis

• Decomposition

• Single replacement

• Double replacement

• Combustion

Multiple Choice

What reaction has the following general formula:
 $C_xH_y\ +\ O_2\ ->CO_{2\ }+\ H_2O$  

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What reaction has the following general formula:

A + B --> AB

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What reaction has the following general formula:

AB + CD --> CB + AD

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What reaction has the following general formula:

AB --> A + B

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

What reaction has the following general formula:

A + CD --> C + AD

• Combination

• Decomposition

• Single Replacement

• Double Replacement

• Combustion

Multiple Choice

Which type of chemical reaction is this:

3Fe + 4H₂O -------- Fe₃O₄ + 4H₂

• synthesis

• single replacement

• decomposition

• double replacement

Multiple Choice

Which type of chemical reaction is this:

C₂H₄ + 3O₂ -------- 2CO₂ + 2H₂O

• double replacement

• decomposition

• combustion

• synthesis