Chemistry Worksheet for 15-Year-Old Students | Science Practice

Instructions

For each question, write your answer in the space provided. Use complete sentences and show your work where necessary.

Section 1: Atomic Structure

• 1. What are the three main parts of an atom?
  
• 2. Name one element that has a atomic number of 6 and describe its position on the periodic table.
  
• 3. What is the difference between an atom and a molecule?
  

Section 2: Chemical Bonding

• 4. Explain the difference between an ionic bond and a covalent bond. Provide an example of each.
  
• 5. Why do atoms form chemical bonds?
  
• 6. What type of bond is formed when electrons are shared between two atoms?
  

Section 3: Stoichiometry

• 7. What is the molar mass of carbon dioxide (COâ‚‚), given that the atomic mass of carbon is 12 g/mol and oxygen is 16 g/mol? Show your calculation.
  
• 8. Explain the concept of a limiting reagent in a chemical reaction.
  
• 9. If a chemical reaction requires 2 moles of hydrogen gas to produce 1 mole of water, how many molecules of hydrogen are needed? (Hint: Use Avogadro's number)
  

Challenge Question

10. Imagine you are a chemist designing a new compound. Describe the type of bond you would use to create a strong and stable molecule. Explain why you chose that type of bond.