1 The closeness of a measured value to the true value is called: A Precision B Accuracy C Error D Average
2 Which of the following best explains why significant figures are used in measurements? A To show the uncertainty in the last digit B To make numbers look longer C To hide errors in measurement D To change the unit of the measurement
4 To reduce parallax error while reading a measuring cylinder, the eye should be: A above the meniscus B below the meniscus C level with the meniscus D far away from the cylinder
5 The process in which large hydrocarbon molecules are broken into smaller ones is called: A Cracking B Combustion C Polymerization D Esterification
6 To measure the volume of a liquid accurately, which piece of apparatus is most suitable? A Beaker B Measuring cylinder C Test tube D Conical flask
7 Percentage error is calculated as: A (Error / True value) × 100 B (True value / Error) × 100 C (Error × True value) / 100 D Error + True value
8 Which of the following best describes a set of measurements that are precise but not accurate? A Close to true value but far from each other B Close to each other but far from true value C Close to true value and close to each other D Far from true value and far from each other
9 Accuracy refers to how close a measured value is to the: A Accepted or true value B Previous reading C Average of many readings D Smallest scale division
10 The process of breaking down large hydrocarbon molecules into smaller ones is called: A Cracking B Combustion C Substitution D Polymerization
11 Which gas is mainly produced during the combustion of hydrocarbons? A Carbon dioxide B Nitrogen C Hydrogen D Oxygen
12 The process of breaking large hydrocarbon molecules into smaller ones is called: A Combustion B Cracking C Halogenation D Hydrogenation
13 Which of the following is the IUPAC name of CH3-CH2-CH2-CH3? A Ethane B Propane C Butane D Pentane
14 Which SI base unit is used for the amount of substance? A Kelvin (K) B Mole (mol) C Candela (cd) D Ampere (A)
15 If a student's measurements are close to each other but far from the true value, the measurements are: A Accurate but not precise B Precise but not accurate C Both accurate and precise D Neither accurate nor precise
17 Which reaction of alkanes takes place in the presence of sunlight with halogens? A Combustion B Substitution C Cracking D Addition
19 Which tool is most suitable for measuring the volume of a liquid accurately in a school laboratory? A Burette B Beaker C Test tube D Conical flask
20 Random errors can be reduced by: A Using a better instrument B Repeating measurements and averaging C Ignoring outliers D Changing the method
21 Repeating a measurement several times and taking the average helps to reduce: A Systematic errors B Random errors C Parallax error D Calibration error
22 When measuring the volume of a liquid with a measuring cylinder, the most appropriate choice depends mainly on the: A Colour of the liquid B Required precision and volume range C Temperature of the room D Shape of the test tube rack
25 A student measures the mass of a sample three times and gets 5.2 g, 5.3 g, and 5.1 g. The true mass is 5.2 g. Which statement best describes the measurements? A They are precise but not accurate. B They are accurate but not precise. C They are both accurate and precise. D They are neither accurate nor precise.