Classify reactions: synthesis, decomposition, replacement, combustion

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   Methane, CH₄, has 4 hydrogen atoms. When one methane molecule burns completely, how many H₂O molecules form, Ari?

   2 H₂O molecules
2. 2.

   Propane, C₃H₈, has 8 hydrogen atoms. When one propane molecule burns completely, how many H₂O molecules form, Bo?

   4 H₂O molecules
3. 3.

   What type of reaction is AgNO₃ + NaCl → AgCl + NaNO₃, Jun?

   • Decomposition
   • Double replacement
   • Single replacement
4. 4.

   What type of reaction is C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O, Kira?

   • Double replacement
   • Combustion
   • Synthesis
5. 5.

   Magnesium and oxygen combine in a synthesis reaction. What is the product, Milo?

   • MgO
   • Mg₂O
   • Mg₂O₃
6. 6.

   Water is split by electricity in a decomposition reaction. What are the products, Noah?

   • H₂ and O₂
   • H₂O₂ and H₂
   • H and O atoms
7. 7.

   Zinc replaces hydrogen in dilute hydrochloric acid, HCl. Which products form, Pia?

   • ZnH₂ and Cl₂
   • ZnCl and H
   • ZnCl₂ and H₂
8. 8.

   Zinc in dilute hydrochloric acid gives off bubbles. Which gas is in them, Ren?

   • Hydrogen
   • Oxygen
   • Chlorine
9. 9.

   When silver nitrate and sodium chloride solutions meet, a white solid forms. What type of reaction is it, Tala?

   • Decomposition
   • Combustion
   • Double replacement
10. 10.

    A copper wire in silver nitrate solution grows gray silver, and the liquid turns blue. What type of reaction is it, Zee?

    • Single replacement
    • Combustion
    • Decomposition