The 15 quiz questions
Question 1 : What is the chemical symbol for gold?
Possible answers:
- Ag
- Au
- Go
- Or
Explanation: The symbol Au comes from the Latin "aurum". Gold (atomic number 79) is a precious metal known since antiquity for its resistance to corrosion.
Question 2 : What is the chemical formula for water?
Possible answers:
- H₂O₂
- OH
- HO₂
- H₂O
Explanation: H₂O means that each water molecule contains 2 hydrogen atoms and 1 oxygen atom bonded by covalent bonds.
Question 3 : Which scientist created the periodic table of elements?
Possible answers:
- Antoine Lavoisier
- Dmitri Mendeleev
- Marie Curie
- John Dalton
Explanation: Dmitri Mendeleev published his periodic table in 1869, classifying elements by atomic mass and predicting the existence of elements not yet discovered.
Question 4 : How many chemical elements does the periodic table currently contain?
Possible answers:
- 92
- 100
- 112
- 118
Explanation: The periodic table has 118 elements, the latest being Oganesson (Og, number 118), officially recognized in 2016.
Question 5 : Which gas makes up about 78% of Earth's atmosphere?
Possible answers:
- Carbon dioxide
- Oxygen
- Nitrogen
- Argon
Explanation: Nitrogen (N₂) makes up 78% of the atmosphere, followed by oxygen (21%), argon (0.9%), and CO₂ (0.04%). It is an inert gas essential to the nitrogen cycle in nature.
Question 6 : Which acid is contained in car batteries?
Possible answers:
- Hydrochloric acid
- Sulfuric acid
- Phosphoric acid
- Nitric acid
Explanation: Sulfuric acid (H₂SO₄) is used in lead-acid batteries. It is one of the most industrially produced acids in the world.
Question 7 : Which chemical element has atomic number 1?
Possible answers:
- Carbon
- Helium
- Lithium
- Hydrogen
Explanation: Hydrogen is the lightest and most abundant element in the universe. Its atom contains only one proton and one electron.
Question 8 : What is a reaction that releases heat called?
Possible answers:
- Athermal
- Isothermal
- Exothermic
- Endothermic
Explanation: An exothermic reaction releases energy in the form of heat. Conversely, an endothermic reaction absorbs heat.
Question 9 : What is the pH of a neutral solution at 25°C?
Possible answers:
- 0
- 1
- 7
- 14
Explanation: A pH of 7 is neutral (neither acidic nor basic). Pure water at 25°C has a pH of 7. Below is acidic, above is basic.
Question 10 : Which gas is the main contributor to the greenhouse effect?
Possible answers:
- Helium (He)
- Nitrogen (N2)
- Carbon dioxide (CO2)
- Oxygen (O2)
Explanation: Carbon dioxide (CO2) is the main human-caused greenhouse gas, primarily from burning fossil fuels. Methane and water vapor also contribute.
Question 11 : Which liquid metal at room temperature was used in thermometers?
Possible answers:
- Lead
- Tin
- Mercury
- Gallium
Explanation: Mercury (Hg) is the only metal that is liquid at room temperature. Its use in thermometers is now banned due to its toxicity.
Question 12 : What is the chemical name of table salt?
Possible answers:
- Sodium carbonate
- Sodium nitrate
- Sodium sulfate
- Sodium chloride
Explanation: Sodium chloride (NaCl) is composed of sodium ions (Na⁺) and chloride ions (Cl⁻). It is the most widely used salt in cooking and industry.
Question 13 : Which element is essential to the structure of all organic molecules?
Possible answers:
- Carbon
- Oxygen
- Nitrogen
- Hydrogen
Explanation: Carbon can form 4 covalent bonds, allowing for complex chains and rings. It is the basis of all organic chemistry and life.
Question 14 : Which scientist discovered polonium and radium?
Possible answers:
- Rosalind Franklin
- Irène Joliot-Curie
- Lise Meitner
- Marie Curie
Explanation: Marie Curie discovered these two radioactive elements with her husband Pierre. She remains the only person to have received two Nobel Prizes in two different sciences.
Question 15 : What type of bond unites the atoms in a water molecule?
Possible answers:
- Covalent bond
- Ionic bond
- Metallic bond
- Hydrogen bond
Explanation: Covalent bonds involve the sharing of electrons between atoms. In H₂O, oxygen shares electrons with both hydrogens.
