1 What is defined as Avogadro's constant, Nᴀ? flag bookmark A The mass contained in one mole of a substance B The volume contained in one mole of a substance C The pressure contained in one mole of a substance D The number of particles contained in one mole of a substance T4 Chapter 3.2 Mole Concept Avogadro's constant is defined as the number of particles in one mole of a substance, which is exactly option D.
2 What is the chemical formula of nitrogen monoxide? flag bookmark A NO B NO₂ C N₂O D N₂O₃ T4 Chapter 3.3 Chemical Formula Nitrogen monoxide contains one nitrogen atom and one oxygen atom, so its formula is NO.
3 Which substance contains double covalent bond? flag bookmark A Oxygen gas B Nitrogen gas C Hydrogen gas D Hydrogen chloride gas T4 Chapter 5.3 Covalent Bond Oxygen gas has a double covalent bond because its two atoms share two pairs of electrons. Nitrogen gas has a triple bond, while hydrogen and hydrogen chloride have single bonds.
4 Which statement is correct about the average rate of reaction? flag bookmark A Rate of reaction at a particular point of time B Rate of reaction that occurs in a particular time interval C Determined by using the graph only D Determined by measuring the tangent gradient to the curve at that point of time T4 Chapter 7.1 Determining Rate of Reaction The average rate of reaction is calculated over a specific time interval, using the change in quantity divided by the time taken. Options A and D describe instantaneous rate, not the average rate.
5 What is the main substance in glass? flag bookmark A Silicon dioxide B Aluminium oxide C Boron oxide D Lead(II) oxide T4 Chapter 8.2 Composition of Glass and Its Uses Glass is primarily made of silicon dioxide (SiO₂), which forms the network structure of ordinary glass.
6 Which of the following are correct about the reduction reaction? I Gain of electrons II Increasing oxidation number III Loss of oxygen IV Loss of hydrogen flag bookmark A I and II B I and III C II and IV D III and IV T5 Chapter 1.1 Oxidation and Reduction Reduction is gain of electrons (I) and loss of oxygen (III); oxidation number decreases, not increases, and hydrogen is gained, not lost. So B is correct.
7 Petroleum is a mixture of simple or long chain hydrocarbon and cannot be used before processing. How are these hydrocarbons separated for daily use? flag bookmark A Through cracking process B Through fractional distillation process C Through electrolysis process D Through distillation and dehydration T5 Chapter 2.1 Types of Carbon Compound Fractional distillation separates crude oil into different hydrocarbon fractions based on their boiling points, making them usable for daily purposes.
8 Which of the following is an endothermic reaction? flag bookmark A Burning of wood B Roast chicken C Welding of railway track D Hot can to heat food T5 Chapter 3.3 Application of Exothermic and Endothermic Reactions in Daily Life Roasting chicken absorbs heat from the surroundings to cook, so it is endothermic. The other options release heat.
9 Which of the following criteria should be prioritized when someone is choosing an effective detergent? flag bookmark A Additives in the detergant B Antioxidant in the detergent C Physical state of detergent D Colour of detergent T5 Chapter 5.2 Cleaning Agents Additives directly determine cleaning performance, e.g., enzymes and builders target different stains. Physical state, colour, and antioxidants do not affect how well a detergent cleans.
10 Which substance has the highest boiling point? flag bookmark A Ethanol B Chlorine C Hydrochloric acid D Ethane T4 Chapter 5.4 Hydrogen Bond Ethanol has the highest boiling point because its molecules form strong hydrogen bonds, which require more energy to overcome than the weak forces in chlorine, ethane, or even hydrogen chloride.