Balancing Chemical Equations Gizmo Answer Key

The Balancing Chemical Equations Gizmo Answer Key provides comprehensive solutions for students learning to balance chemical equations. It covers key concepts such as reactants, products, and the importance of coefficients and subscripts in chemical formulas. This resource is ideal for high school chemistry students preparing for exams or completing homework assignments. The answer key includes balanced equations for various reactions, including synthesis, decomposition, and combustion. It serves as a valuable tool for understanding chemical reactions and mastering the balancing process.

Key Points

Includes detailed solutions for balancing chemical equations in high school chemistry.
Covers various types of chemical reactions such as synthesis, decomposition, and combustion.
Provides explanations of coefficients and subscripts in chemical formulas.
Ideal for students preparing for chemistry exams or completing homework assignments.

148

2018

Name: ______________________________________ Date: ________________________

Student Exploration: Balancing Chemical Equations

Vocabulary: coefficient, combustion, compound, decomposition, double replacement, element,

molecule, product, reactant, single replacement, subscript, synthesis

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

The scouts are making s’mores out of toasted marshmallows, chocolate, and graham crackers.

1. What is wrong with the image below? ___________________________________________

2. Assuming a s’more requires two graham crackers, one marshmallow, and one piece of

chocolate, how many s’mores could you make with the ingredients shown? _____________

Gizmo Warm-up

In a chemical reaction, reactants interact to form products.

This process is summarized by a chemical equation. In the

Balancing Chemical Equations Gizmo, look at the floating

molecules below the initial reaction: H

+ O

→ H

1. How many atoms are in a hydrogen molecule (H

)? ___

2. How many atoms are in an oxygen molecule (O

)? ____

3. How many hydrogen and oxygen atoms are in a water molecule (H

O)? ________________

4. In general, what does a subscript (such as the “2” in H

) tell you about the molecule?

_________________________________________________________________________

5. A chemical equation is balanced if the number of each type of atom on the left side is equal

to the number of each type on the right side. Is this reaction balanced? ________________

2018

Activity A:

Balancing

equations

Get the Gizmo ready:

• Check that the Synthesis reaction is selected and

that all coefficients are set to one. (The

coefficients are the numbers in the boxes.)

Introduction: The equation H

+ O

→ H

O is unbalanced because there are two oxygen atoms

on the reactants side of the equation, and only one on the products side of the equation. To

balance the equation, you cannot change the structure of any of the molecules, but you can

change the number of molecules that are used.

Question: How are chemical equations balanced?

1. Balance: Turn on Show histograms. The equation is balanced when there are equal

numbers of each type of atom represented on each side of the equation.

In the Gizmo, use the up and down arrows to adjust the numbers of hydrogen, oxygen, and

water molecules until the equation is balanced. When you are done, turn on Show

summary to check your answer.

Write the balanced equation here: _____ H

+ _____ O

→ _____ H

2. Solve: Turn off Show summary. Use the Choose reaction drop down menu to see other

equations, and balance them. Check your answers and then write the balanced equations.

_____ Al + _____ HCl → _____ AlCl

+ _____ H

_____ NaCl → _____ Na + _____ Cl

_____ Na

S + _____ HCl → _____ NaCl + _____ H

_____ CH

+ _____ O

→ _____ CO

+ _____ H

3. Practice: Balance the following chemical equations. (These equations are not in the Gizmo.)

A. _____ Na + _____ Cl

→ _____ NaCl

B. _____ Na + _____ H

O → _____ NaOH + _____ H

C. _____ Mg + _____ O

→ _____ MgO

D. _____ KClO

→ _____ KCl + _____ O

E. _____ Al + _____ CuO → _____ Al

+ _____ Cu

F. _____ I

+ _____ Na

→ _____ NaI + _____ Na

G. _____ Mg + _____ P

→ _____ Mg

2018

Activity B:

Classifying

reactions

Get the Gizmo ready:

• Turn off Show summary and Show histograms.

Introduction: Chemical equations show how compounds and elements react with one

another. An element is a substance consisting of one kind of atom, such as aluminum (Al) or

oxygen gas (O

). A compound is a substance made of more than one kind of atom, such as

water (H

O) or table salt (NaCl).

Question: How are chemical reactions classified?

1. Match: Most chemical reactions can be classified as one of four types. Using the chemical

equations in the Gizmo as a guide, match the following definitions to the type of reaction.

____ One reactant is broken down into two or

more products.

____ A fuel combines with oxygen to produce

carbon dioxide (CO

) and water (H

O).

____ Two or more reactants combine to form

one product.

____ Two compounds react to form two

different compounds.

____ A compound reacts with an element to

form a new compound and a different

element.

A. Synthesis

B. Decomposition

C. Single replacement

D. Double replacement

E. Combustion

2. Practice: Balance each of the chemical equations below. (Some equations may already be

in balance.) In the space to the right, classify the reaction as a synthesis, decomposition,

single replacement, double replacement, or combustion.

A. ___ AgNO

+ ___ KCl → ___ AgCl + ___ KNO

_______________________

B. ___ H

O + ___ SO

→ ___ H

_______________________

C. ___ KI + ___ Cl

→ ___ KCl + ___ I

_______________________

D. ___ NaHCO

→ ___ Na

+ ___ H

O + ___ CO

_______________________

E. ___ Zn + ___ HCl → ___ ZnCl

+ ___ H

_______________________

F. ___ BaCl

+ ___ Na

→ ___ BaSO

+ ___ NaCl _______________________

G. ___ C

+ ___ O

→ ___ CO

+ ___ H

O _______________________

H. ___ Al + ___ CuCl

→ ___ AlCl

+ ___ Cu _______________________

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FAQs of Balancing Chemical Equations Gizmo Answer Key

What types of chemical reactions are covered in the Gizmo answer key?

The Gizmo answer key covers several types of chemical reactions, including synthesis, decomposition, single replacement, double replacement, and combustion. Each type is illustrated with examples, allowing students to see how different reactants combine to form products. Understanding these classifications helps students grasp the fundamental concepts of chemical reactions and their balancing. The answer key also provides specific balanced equations for practice, reinforcing these concepts.

How does the answer key help students learn to balance equations?

The answer key assists students in learning to balance chemical equations by providing step-by-step solutions and explanations for each reaction. It emphasizes the importance of maintaining equal numbers of atoms on both sides of the equation, which is crucial for understanding the law of conservation of mass. By working through the examples in the answer key, students can practice adjusting coefficients to achieve balance, gaining confidence in their ability to tackle similar problems independently. This hands-on approach enhances their comprehension of chemical principles.

What is the significance of coefficients and subscripts in chemical equations?

Coefficients and subscripts play a vital role in chemical equations by indicating the number of molecules involved in a reaction. Coefficients represent the quantity of each molecule, while subscripts denote the number of atoms within a molecule. Understanding these elements is essential for balancing equations correctly, as they ensure that the same number of each type of atom is present on both sides of the equation. This knowledge is foundational for students studying chemistry, as it underpins many concepts related to chemical reactions.