Q1 Easy
In the reaction: 2H₂ + O₂ → 2H₂O, how many moles of water are produced from 4 moles of hydrogen gas?
A 2 moles B 4 moles C 8 moles D 6 moles
Q2 Easy
What is the chemical formula of table salt produced when hydrochloric acid reacts with sodium hydroxide?
A NaCl B NaOH C HCl D Na₂O
Q3 Easy
Which of the following is a characteristic feature of a chemical reaction?
A Formation of new substances with different chemical properties B Change in the physical appearance of matter only C Reversible process that does not involve energy change D Change in state without breaking chemical bonds
Q4 Easy
Which of the following is a physical property that distinguishes metals from non-metals?
A Metals are malleable and ductile, while non-metals are brittle B Metals are poor conductors of electricity, while non-metals are good conductors C Metals have low melting points, while non-metals have high melting points D Metals are transparent, while non-metals are opaque
Q5 Easy
When iron reacts with oxygen to form iron oxide, this type of reaction is classified as:
A Decomposition reaction B Displacement reaction C Combination reaction D Combustion reaction
Q6 Easy
Which of the following substances is a strong acid?
A Acetic acid B Hydrochloric acid C Carbonic acid D Citric acid
Q7 Easy
Which of the following statements about the periodic table is correct?
A Atomic radius increases from left to right in a period B Atomic radius decreases from top to bottom in a group C Atomic radius increases from top to bottom in a group D Atomic radius is the same for all elements in a period
Q8 Easy
An element has 4 electrons in its outermost shell and is in Period 2. What is its atomic number?
A 4 B 6 C 8 D 14
Q9 Easy
What is the molecular mass of CO₂ (carbon dioxide)? [Atomic masses: C = 12, O = 16]
A 28 u B 44 u C 32 u D 36 u
Q10 Easy
When a non-metal reacts with oxygen, the resulting compound is typically:
A Basic in nature B Acidic in nature C Neutral D Metallic
Q11 Easy
What is the atomic mass unit (amu) approximately equal to?
A 1/12th of the mass of a carbon-12 atom B 1/16th of the mass of an oxygen atom C The mass of one electron D The mass of one proton only
Q12 Easy
Which type of chemical reaction occurs when a single compound breaks down into two or more simpler substances?
A Combination reaction B Decomposition reaction C Displacement reaction D Double displacement reaction
Q13 Easy
When a metal reacts with oxygen, it typically forms a/an:
A Acid B Base or metallic oxide C Salt D Non-metal compound
Q14 Easy
What is the pH value of a neutral solution at 25°C?
A 7 B 0 C 14 D 1
Q15 Easy
Which of the following correctly defines a molecule?
A A group of two or more atoms chemically bonded together B A single atom of any element C A negatively charged particle found in an atom D The smallest unit of a compound that retains its properties
Q16 Easy
Which element is a non-metal but conducts electricity in its solid state?
A Sulfur B Carbon (graphite) C Oxygen D Chlorine
Q17 Easy
If an element has an atomic number of 8, how many electrons does a neutral atom of this element have?
A 4 electrons B 8 electrons C 16 electrons D 2 electrons
Q18 Easy
Which of the following elements is located in Period 3, Group 17 of the modern periodic table?
A Chlorine B Fluorine C Bromine D Iodine
Q19 Easy
The atomic number of an element is 12. Which block of the periodic table does this element belong to?
A s-block B p-block C d-block D f-block
Q20 Easy
A solution has a pH of 9. Is this solution acidic, basic, or neutral?
A Acidic B Neutral C Basic D Cannot be determined