1 Benzene is a typical example of: A Aliphatic hydrocarbons B Aromatic hydrocarbons C Alkynes D Saturated hydrocarbons
2 Which of the following will undergo an addition reaction most readily? A Methane B Ethane C Ethene D Propane
3 Precision describes how close repeated measurements are to: A The true value B Each other C The largest scale mark D The SI unit
5 The combustion of alkanes in excess oxygen produces: A Carbon monoxide and water B Carbon dioxide and water C Carbon and hydrogen D Only carbon dioxide
6 A student measures the mass of a sample three times: 2.50 g, 2.52 g, and 2.49 g. The actual mass is 2.60 g. Which statement best describes the student's measurements? A The measurements are precise but not accurate. B The measurements are accurate but not precise. C The measurements are both accurate and precise. D The measurements are neither accurate nor precise.
7 A student takes repeated readings of the same measurement. The readings are very close to each other but far from the true value. This shows: A High accuracy and high precision B High accuracy and low precision C Low accuracy and high precision D Low accuracy and low precision
8 What is the main purpose of calibrating a thermometer? A To change its size B To make it look shiny C To ensure accurate readings D To increase its weight
9 A student obtained the following four readings for the volume of a liquid: 20.1 mL, 20.2 mL, 20.0 mL, and 20.1 mL. These readings are: A Accurate but not precise B Precise but not necessarily accurate C Both accurate and precise D Neither accurate nor precise
10 Which instrument is used to measure temperature accurately in the laboratory? A Thermometer B Barometer C Hydrometer D Manometer
11 A measurement that is both accurate and precise is: A Close to the true value and to other readings B Close to the true value but not to other readings C Close to other readings but not to the true value D Far from both the true value and other readings
12 What is the product of complete combustion of methane? A CO and H2O B CO2 and H2O C C and H2 D CO2 and H2
13 The reaction of alkanes with halogens in the presence of sunlight is called: A Combustion B Substitution C Cracking D Addition
14 What is the process of breaking large hydrocarbon molecules into smaller ones called? A Combustion B Cracking C Substitution D Addition
15 What is the main purpose of calibrating a measuring instrument? A To make it look neat B To increase its size C To ensure accurate readings D To change its unit
16 What does repeating a measurement help to reduce? A Systematic error B Random error C Parallax error D Zero error
17 Which of the following is a product of complete combustion of alkanes? A CO B C C CO2 and H2O D H2
18 Which of the following is a systematic error? A A balance that always reads 0.5 g too high B A student reading a scale slightly differently each time C Bubbles forming randomly in a liquid D Small changes in room temperature during the experiment
19 Which gas is produced when alkanes burn completely in oxygen? A Carbon monoxide B Carbon dioxide C Hydrogen D Nitrogen
21 Which gas is mainly produced when alkanes burn completely in excess oxygen? A Carbon monoxide B Carbon dioxide C Methane D Hydrogen
22 What is the main product of complete combustion of alkanes? A Carbon monoxide B Carbon dioxide and water C Soot and water D Alcohol
25 A student calculates the percentage error as 2.5%. What does this value indicate? A The measurement is exactly correct. B The error is 2.5% of the true value. C The precision is 2.5%. D The systematic error is 2.5 units.