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Grade 12 Compounds & Molecules Worksheet with Answers

Grade 12 (US) · Year 13 (UK) · Class 12 (India) · Chemistry

Unit 5: ReviewMixed Chemistry ReviewNGSS HS-PS1-2

How elements combine into compounds and molecules, and reading chemical formulas. This free high school worksheet has 12 questions and a full answer key. Print it or save it as a PDF — every answer is checked by code, not guessed.

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Compounds & Molecules

Grade 12 · Chemistry

Score___ / 12

Name

Class

Date

Learning goal: Mixed Chemistry Review · NGSS HS-PS1-2

Directions: This worksheet has 2 parts. Read the instructions at the start of each part.

Example

What is a substance made of only one type of atom called?

Answer: an element

RememberAtoms, elements and compounds

H₂O2 hydrogen atoms (the small 2)1 oxygen atom (no number = 1)Atomsmallest pieceElementone kind of atom: OMoleculeatoms bonded: O₂Compounddifferent elements: CO₂Mixturenot bonded: salt water
Part A

Match each clue to the right word. Write the letter in the box.

  1. 1What do we call two or more atoms bonded together?
  2. 2What is the chemical formula for water?
  3. 3What type of bond forms when electrons are transferred, as in NaCl?
  4. 4What is the chemical formula for oxygen gas?
  5. 5What is the chemical formula for table salt?
  6. 6What is the chemical formula for methane?
  • ANaCl
  • BMolecule
  • CH₂O
  • DO₂
  • EIonic bond
  • FCH₄
Part B

Answer each question. Use full sentences where you can.

  1. 7

    How many atoms are in one molecule of H₂O?

  2. 8

    How many atoms of each element are in one molecule of CO₂?

  3. 9

    What do we call a combination of substances that are not chemically bonded, like salt water?

  4. 10

    How many atoms in total are in one molecule of glucose, C₆H₁₂O₆?

  5. 11

    What do we call a substance made of two or more elements chemically bonded?

  6. 12

    Can a compound be separated by physical methods like filtering?

★ Challenge corner for fast finishers

Why do you see lightning before you hear thunder?

How did I do?

Teacher's comments

Free printable worksheets with answer keys · aethelsystems.com/worksheets/chemistry/12/chemistry_compounds

Answer key (click to show)
  1. 1.B — a molecule
  2. 2.C — H₂O
  3. 3.E — an ionic bond
  4. 4.D — O₂
  5. 5.A — NaCl
  6. 6.F — CH₄
  7. 7.3 (2 hydrogen, 1 oxygen)
  8. 8.1 carbon and 2 oxygen
  9. 9.a mixture
  10. 10.24
  11. 11.a compound
  12. 12.no, it needs a chemical reaction; mixtures can be separated physically
  13. ★light travels much faster than sound (challenge corner)

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