1.1

Question 1

Front: Who proposed the Plum Pudding Model of the atom?

Answer 1

Back: J.J. Thomson

Question 2

Front: What did Democritus propose about the nature of atoms?

Answer 2

Back: Democritus proposed that atoms were indivisible spheres, with the Greek word “atomos” meaning indivisible.

Question 3

Front: What was the main component of J.J. Thomson’s Plum Pudding Model?

Answer 3

Back: Electrons were embedded in a positively charged “pudding” to maintain overall electrical neutrality.

Question 4

Front: What experiment led to the rejection of the Plum Pudding Model?

Answer 4

Back: Rutherford’s Alpha Particle Scattering Experiment

Question 5

Front: Who conducted the Alpha Particle Scattering Experiment?

Answer 5

Back: Ernest Rutherford, along with his students Hans Geiger and Ernest Marsden.

Question 6

Front: What was the conclusion drawn from Rutherford’s experiment?

Answer 6

Back: Atoms are mostly empty space, with a small, heavy, positively charged nucleus.

Question 7

Front: What replaced the Plum Pudding Model of the atom?

Answer 7

Back: Rutherford’s Nuclear Model

Question 8

Front: Who proposed the Bohr Model of the atom?

Answer 8

Back: Niels Bohr

Question 9

ront: What is a key feature of the Bohr Model?

Answer 9

Back: Electrons orbit the nucleus at different distances, in distinct energy levels

Question 10

Front: What were some successes of the Bohr Model?

Answer 10

Back: It explained findings from experiments better than previous models, could explain absorption and emission of electromagnetic radiation, and theoretical calculations agreed with experimental results

Question 11

Front: What are the three main components of an atom and their charges?
Back:

Answer 11

Protons: Positively charged particles with a relative atomic mass of one unit.
Neutrons: Neutral particles with no charge and a relative atomic mass of one unit.
Electrons: Negatively charged particles with almost no mass, approximately 1/2000 the mass of a proton or neutron.

Question 12

Front: What is the approximate radius of an atom?

Answer 12

Back: An atom has an incredibly small radius of approximately 1 × 10^-10 meters, or 0.0000000001 meters when written without standard form

Question 13

Front: How is density defined?

Answer 13

Back: Density is defined as the mass per unit volume of a material.

Question 14

Front: What equation is used to calculate density?

Answer 14

Back: Density (ρ) equals mass (m) divided by volume (V), expressed as ρ = m/V.

Question 15

Front: What are the approximate densities of the following materials in kg/m³?
³

Answer 15

Back:

Air: 1.3 kg/m³
Wood: 300-800 kg/m³ (depending on species)
Water: 1000 kg/m³
Granite (stone): 2700 kg/m³
Lead: 11300 kg/m

Question 16

Front: How do the densities of solids, liquids, and gases compare?
Back:

Answer 16

Solids and liquids have similar densities because their molecules are tightly packed together, whereas in gases, molecules are widely separated.
The density of gases is significantly lower than that of solids or liquids. For example, the density of air at sea level and room temperature is approximately 1.3 kg/m³, while the density of water is 1000 kg/m³.

Question 17

Front: What is the aim of Experiment 1: Measuring the density of regularly shaped objects ?

Answer 17

Back: The aim of Experiment 1 is to determine the densities of regular objects by using measurements of their dimensions

Question 18

Front: What is the aim of Experiment 2 for Measuring the Density of Irregularly Shaped Objects?

Answer 18

Back: The aim of Experiment 2 is to determine the densities of irregularly shaped objects using a displacement technique. This method involves submerging the object in water within a Eureka can and measuring the volume of water displaced, which is equal to the volume of the object.

Question 19

Front: What is the aim of Experiment 3 for Measuring Density of Liquids?

Answer 19

Back: The aim of Experiment 3 is to determine the density of a liquid by finding a difference in its mass. This is achieved by measuring the mass of an empty measuring cylinder, filling it with the liquid, and measuring the new mass, then calculating the density using the volume of the liquid.

Question 20

Front: What are some systematic errors, random errors, and safety considerations for evaluating the experiments?
Back:

Answer 20

Systematic Errors:
Ensure the digital balance is set to zero before taking measurements of mass, including when measuring the density of the liquid.
Random Errors:
Take repeat readings and calculate an average to minimize errors in measurements of length.
Carefully place the irregular object in the displacement can to prevent water splashing, which can lead to incorrect volume readings.
Safety Considerations:
Handle glassware carefully to prevent breakage.
Avoid pouring water into the measuring cylinder while it is on the electric balance to prevent electric shock.
Stand up during the experiment to react quickly to any spills.