Gizmo - Student Exploration: Balancing Chemical Equations Answer key Download To Score A verified answers-2023

Student Exploration: Balancing Chemical Equations

Directions: Follow the instructions to go through the simulation. Respond to the

questions and prompts in the orange boxes.

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?

There are not ingredients shown to make the amount of smores

shown

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?

2

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: H2 + O2 ???? H2O.

1. How many atoms are in a hydrogen molecule (H2)? 2

2. How many atoms are in an oxygen molecule (O2)? 2

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

molecule (H2O)?

3

4. In general, what does a subscript (such as the “2” in H2) tell

you about the molecule?

How

many

molec

ules

there

are

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?

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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 H2 + O2 ???? H2O 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: 2 H2 + 1 O2 ???? 2 H2O

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.

2 Al + 6 HCl ???? 2 AlCl3 + 3 H2

2 NaCl ???? 2 Na + 1 Cl2

1 Na2S + 2 HCl ???? 2 NaCl + 1 H2S

CH4 + O2 ???? CO2 + H2O

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

A. 2 Na + 1 Cl2 ???? 2 NaCl

B. 2 Na + 2 H2O ???? 4 NaOH + 1 H2

C. 2 Mg + 1 O2 ???? 2 MgO

D. 2 KClO3 ???? 2 KCl + 3 O2

E. 4 Al + 6 CuO ???? 2 Al2O3 + 6 Cu