IB myp 4-5 Chemistry – Practice Questions- All Topics
Topic :Types of chemical reaction-Formation of salts
Topic :Types of chemical reaction-Weightage : 21 %
All Questions for Topic :acids and bases,neutral solutions,acid/base reactions,$\mathrm{pH}$ and indicators,formation of salts,uses of salts,redox reactions,reactivity series,extraction of metals and corrosion,electrochemical cells
Question (10 marks)
Cola is a popular soft drink that contains dissolved carbon dioxide gas, which creates bubbles. Originally made from kola nuts, it was first sold as a headache and indigestion remedy.
Question a (1 mark)
State why the gas is named carbon dioxide rather than carbon oxide.
▶️Answer/Explanation
Answer:
Because it contains two oxygen atoms bonded to one carbon atom (CO2).
Explanation:
The prefix “di-” in dioxide indicates two oxygen atoms, following IUPAC naming conventions for covalent compounds.
Question b (1 mark)
State the chemical formula of carbon dioxide.
▶️Answer/Explanation
Answer:
CO2
Explanation:
The formula shows one carbon atom covalently bonded to two oxygen atoms.
Question c (3 marks)
Draw the Lewis (electron dot) structure of carbon dioxide.
▶️Answer/Explanation
Answer:
O::C::O (with double bonds between C and each O)
Explanation:
Carbon shares two electron pairs with each oxygen atom to complete their octets, forming a linear molecule.
Question d (2 marks)
Represent the equilibrium between dissolved CO2 in cola and gaseous CO2 in the headspace using state symbols.
▶️Answer/Explanation
Answer:
CO2(aq) ⇌ CO2(g)
Explanation:
The equation shows the dynamic equilibrium between aqueous CO2 (dissolved in liquid) and gaseous CO2 in the space above the drink.
Question e (3 marks)
Explain what happens to dissolved CO2 concentration when a cold cola can is opened on a warm day.
▶️Answer/Explanation
Answer:
• CO2 solubility decreases with temperature
• Gas escapes as bubbles when pressure is released
• Dissolved concentration decreases over time
Explanation:
Henry’s Law explains that gas solubility decreases with temperature increase and pressure decrease, causing CO2 to come out of solution.
Question:
Construct balanced half-equations for the reactions occurring at the anode and the cathode, and the overall chemical equation.
▶️Answer/Explanation
Ans: Anode: 2Cl–(l) → Cl2(g)+ 2e–
Cathode: Zn2+(l) + 2e– → Zn(s)
Overall: 2Cl–(l) + Zn2+(l) → Cl2(g) + Zn(s)