Gizmo Chemical Equations Answer Key

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Chemical Equations is one of the science materials on Gizmo that allows you to set up an equation in the chemical formulas text boxes. You just simply type in ‘H2 + O2’ in the Reactants box and ‘H2O’ in the Products box. This input will represent the reaction of hydrogen and oxygen gas to form water.

After learning about Chemical Equations, you can take the Chemical Equation test on Gizmo and of course, you should answer all the questions correctly. If you really need the Chemical Equations answer keys, don’t leave this page, since we will show you the questions and answers of the Chemical Equation test on Gizmo. Let’s check them out!

Gizmo Chemical Equation Answers

We finally found the answers of the Gizmo Chemical Equation test from This website frequently shows you the kinds of the answers for every subject. The test consists of four sections including Warming up, Activity, A, B and C. We will show you the correct answers of the Gizmo Chemical Equation test that are highlighted in bold font.

Warming Up

There are also two questions available on the Warming Up section. It shows you the following formula:

Reactants (H2 + O2) à Products (H2O)

  1. Check that the Visual display is chosen on each side of the Gizmo, and count the atoms.
    A. How many hydrogen atoms are on the Reactants side?2 Products side? 2
    B. How many oxygen atoms are on the Reactants side?  Products side? 1
  2. Based on what you see, is this equation currently balanced? No

Activity A – Interpreting Chemical Formulas


To balance a chemical equation, you first need to be able to count how many atoms of each element are on each side of the equation. In this activity, you will practice counting the atoms that are represented in chemical formulas.

Question: How do we read chemical formulas?

  1. Observe: Type “H2” into the Reactants box and hit Enter on your keyboard. Note that the formula is shown as H2 below. The small “2” in H2 is a subscript.
    a. What does the “2” in H2 represent? There are two hydrogens
    b. In general, what do you think a subscript in a chemical formula tells you? How many of an element there is
    c. Try typing in other subscripts next to the H, such as 3, 4, and 5. Is your answer to question B still true? Explain.
    Yes, it would make it to where there are 3, 4 and 5 Hydrogens.
  2. Count: Clear the Reactants box, and type in a more complex chemical formula: “Ca(OH)2.” Look at the number of atoms shown.
    a. How many of each type of atom do you see?      Ca: 1     O: 2    H: 2
    b. In general, what happens when a subscript is found outside of parentheses? You times it by number in parentheses.
    c. Try typing in other subscripts next to the (OH), such as 3, 4, and 5. Is your answer to question B still true? Explain.
    Yes, I would times 1 by 3, 4, and 5
  3. Practice: For each of the real chemical formulas below, calculate how many of each element there are. Check your answers for the first three formulas using the Gizmo.

AgCl3Cu2 → Ag: 1    Cl: 3    Cu: 2

Ba(AsO4)2 → Ba: 1    As: 2    O: 8

(NH4)3PO4 →  N: 3    H: 12    P: 1    O: 4

MnPb8(Si2O7)3 → Mn: 1   Pb: 8   Si: 6    O: 21

Activity B – Balancing Equations


In a chemical reaction, the reactants are the substances that enter into the reaction, and the products are the substances that are made in the reaction. A chemical reaction is balanced if the numbers of reactant atoms match the numbers of product atoms.

Goal: Learn to balance any chemical equation

  1. Observe: To model how hydrogen and oxygen react to make water, type “H2+O2” into the Reactants box and “H2O” into the Products box.
    As the equation is written, which element is not in balance? Oxygen
    Explain: There is one on one side and 2 on the other.
  2. Balance: To balance a chemical equation, you are not allowed to change the chemical formulas of the substances involved in the reaction. You are allowed to change the number of molecules of each substance by adding coefficients in front of the formulas.
    a. To balance the oxygen atoms, add a “2” in front of the “H2O” in the Products box.   How many oxygen atoms are found on each side of the equation now? 2
    b. To balance the hydrogen atoms, add a “2” in front of the “H2” in the Reactants box.   How many hydrogen atoms are found on each side of the equation now? 4
    c. Is this equation currently balanced? Yes, Click Show if balanced to check
  3. Apply: Now enter a more complex chemical reaction: Ca(OH)2 + HBr  CaBr2 + H2O. List the numbers of each element in the tables below:
Ca O H Br
1 2 3 1
Ca O H Br
1 1 2 2

a. Which elements are out of balance? Oxygen, Hydrogen, Bromine
b. Add coefficients to balance first the bromine (Br) and then the hydrogen (H) atoms. When the equation is balanced, write the complete formula below:Ca (OH)2 + 2 HBr à CaBr2 + 2H2O

  1. Practice: Chemical reactions are generally classified into five groups, defined below. Balance each equation, using the Gizmo for help.

Combination (or synthesis) – two or more elements combine to form a compound.
Na + O2 → Na2O                               4Na + O2 → 2Na2O
La2O3 + H2O → La(OH)3                La2O3 + 3H2O → 2 La (OH) 3
N2O5 + H2O → HNO3                      N2O5 + H2O → 2HNO3

Decomposition – a compound breaks down into elements and/or simpler compounds.
KNO3 → KNO2 + O2                        2KNO3 → 2KNO2 + O2
NaN3 → Na + N2                               2NaN3  → 2Na + 3N2
NH4NO3 → N2O + H2O                   NH4NO3 → N2O + 2H2O

Combustion – a fuel reacts with oxygen to release carbon dioxide, water, and heat.
CH4 + O2 → CO2 + H2O                  CH4 + 2O2 → CO2 + 2 H2O
C3H8 + O2 → CO2 + H2O                C3H8 + 5O2 → 3 CO2 + 4H2O
C6H12O6 + O2 → CO2 + H2O         C6H12O6 + 6O2 → 6CO2 + 6H2O

Single replacement – an element replaces another element in a compound.
KCl + F2 → KF + Cl2                        2KCI + F2 → 2KF + CI2
Mg + HCl → MgCl2 + H2                 Mg + 2HCI → MgCI2 + H2
Cu + AgNO3 → Cu(NO3)2 + Ag      Cu + 2AgNO3 → Cu (NO3) 2 + 2 Ag

Double replacement – two compounds switch parts with one another.
AgNO3 + K2SO4 → Ag2SO4 + KNO3 –  2AgNO3 + K2SO4 → Ag2SO4 + 2KNO3
Mg(OH)2 + HCl → MgCl2 + H2O – Mg (OH)2 + 2HCI → MgCI2 + H2O
Al(OH)3 + H2SO4 → Al2(SO4)3 + H2O – 2AI(OH)3 + H2SO4 → AI2(SO4)3 + H2O

As we’ve mentioned, Gizmo Chemical Equation has three activity tests to answer. However, we can only show you two activity tests (Activity A and Activity B). So, if you want to get a complete Gizmo Chemical Equations answer, you can visit

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