Who proposed the planetary model of the atom with electrons orbiting the nucleus?
Erwin Schrödinger
Ernest Rutherford
Niels Bohr
J.J. Thomson
Correct answer is C
Niels Bohr proposed the planetary model of the atom in 1913. According to this model, electrons move in circular orbits around the positively charged nucleus, much like planets orbiting the sun. However, this model has been refined in modern quantum theory.
What is the name of the process by which ammonia is produced on an industrial scale?
Nitrogenation
Ammoniation
Nitrification
Haber process
Correct answer is D
The industrial production of ammonia is known as the Haber process. It involves the reaction of nitrogen gas (N\(_2\)) and hydrogen gas (H\(_2\)) at high temperature and pressure in the presence of a catalyst to produce ammonia (NH\(_3\)).
The release of harmful chemicals into water bodies
The excessive growth of algae due to nutrient enrichment
The presence of heavy metals in water
The formation of oil slicks on water surfaces
Correct answer is B
Eutrophication is the excessive growth of algae and aquatic plants in water bodies due to the increased availability of nutrients like nitrogen and phosphorus. This nutrient enrichment often comes from agricultural runoff, sewage, and industrial discharges.
According to the kinetic theory of gases, the pressure exerted by a gas is due to
The vibrations of gas particles.
The weight of the gas particles
The attractive forces between gas particles
The collisions of gas particles with the container walls
Correct answer is D
In the kinetic theory of gases, the pressure exerted by a gas is a result of the frequent and random collisions of gas particles with the walls of the container. The force of these collisions creates pressure on the container walls.
What is the sum of the oxidation numbers in a neutral compound?
+2
-1
0
+1
Correct answer is C
The sum of the oxidation numbers in a neutral compound is always zero. This is because oxidation numbers represent the charge that an atom would have if all bonding were ionic. In a neutral compound, the total positive charge (from the oxidation numbers of the atoms that have positive oxidation numbers) must equal the total negative charge (from the atoms that have negative oxidation numbers).