JAMB Chemistry Past Questions & Answers - Page 3

Chlorine gas is used in the production of chlorofluorocarbons (CFCs), which were once widely used as refrigerants, aerosol propellants, and foam-blowing agents. However, due to their harmful impact on the ozone layer, their use has been significantly reduced.

Temperature must be expressed in Kelvin when using the ideal gas law. The Kelvin scale is an absolute temperature scale, and its zero point (0 K) corresponds to absolute zero, the point at which the kinetic energy of gas particles is minimal.

Fluorine is a halogen that is a gas at room temperature and is pale yellow in color. Halogens are a group in the periodic table consisting of five chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Among these, only Fluorine and Chlorine are gases at room temperature, but Chlorine is greenish-yellow, not pale yellow.

A calorimeter is a device used to measure the heat of reaction experimentally. It is designed to isolate the reaction from the surroundings and measure the temperature change in the surroundings to calculate the heat exchanged.

To calculate the mass of a substance, we can use the formula:
Mass = Volume x Density
Given the volume of ethanol is 500 mL and the density of ethanol is 0.789 g/mL, we can plug the values into the formula:
Mass = 500 mL x 0.789 g/mL = 394.5 g