Grade 10 · Science · Chemistry

10th grade Balance chemical equations worksheet

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Balance chemical equations

Grade 10 Science Worksheet

NameDate

Circle the best answer, or write your answer on the line.

In 3 Ca(NO₃)₂, the coefficient is 3, there are 2 nitrate groups per unit and 3 oxygens per nitrate. How many oxygen atoms in all, Ari?
In 2 Al₂(SO₄)₃, the coefficient is 2, there are 3 sulfate groups per unit and 4 oxygens per sulfate. How many oxygen atoms in all, Bo?
In 3 (NH₄)₂CO₃, the coefficient is 3, there are 2 ammonium groups per unit and 4 hydrogens per ammonium. How many hydrogen atoms in all, Esme?
4.
Which coefficients balance Mg + O₂ → MgO, Jun?
- 1, 2, 2
- 2, 1, 2
- 1, 1, 1
5.
Which coefficients balance Na + Cl₂ → NaCl, Kira?
- 2, 2, 1
- 1, 2, 1
- 2, 1, 2
6.
In CaCO₃ → CaO + CO₂, why can't carbonate be counted as a unit, Milo?
- Carbonate has no charge
- It breaks apart into CaO and CO₂
- Calcium is a polyatomic ion here
7.
Why balance a polyatomic ion as one unit when it stays whole, Pia?
- It saves counting each atom
- It changes the ion's overall charge
- It adds atoms
8.
Which is the balanced equation for calcium carbonate → calcium oxide + carbon dioxide, Ren?
- CaC → CaO + O₂
- CaCO₃ → CaO₂ + C
- CaCO₃ → CaO + CO₂
9.
Which is the balanced equation for hydrogen + oxygen → water, Tala?
- H₂ + O₂ → H₂O₂
- H + O → HO
- 2 H₂ + O₂ → 2 H₂O
10.
In a word equation, how is the element oxygen written, Zee?
- O₂
- O
- O₃

Balance chemical equations. Every version has 10 questions, and the answer key prints on the second page.

I can count atoms from coefficients and subscripts, including through brackets.
I can balance equations by choosing coefficients, never changing subscripts, and write them in lowest terms.
I can keep a polyatomic ion together when it appears unchanged on both sides, and turn word equations into formulas.
I can balance hydrocarbon combustion: O₂ needed = C + H ÷ 4.

Standard: HS-PS1-7

coefficient: The number in front of a formula; it multiplies the whole formula

subscript: The small number in a formula; fixed for that substance

balanced equation: An equation with equal atoms of each element on both sides

combustion: Burning in oxygen; a hydrocarbon makes CO₂ and H₂O

conservation of mass: Atoms are rearranged, never made or destroyed

Your child added the coefficient and subscript. The coefficient multiplies every atom in the formula: atoms = coefficient × subscript.

Your child counted one formula unit. The coefficient in front multiplies everything, including the brackets.

Your child gave each H its own oxygen atom. Four H make two H₂O, which take one O₂: O₂ needed = C + H ÷ 4.

What is the most common mistake with balance chemical equations?

Your child added the coefficient and subscript. The coefficient multiplies every atom in the formula: atoms = coefficient × subscript.

Are these 10th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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