CHEMTEST : CHAPTER 2 FORM 4 (MATTER & THE ATOMIC STRUCTURE)

What is matter?

• Matter is anything that has energy and occupies space

• Matter is anything that has mass and occupies space

• Matter is anything that has volume and color

• Matter is anything that has volume and temperature

Answer explanation

Matter is the term for any substances that takes up space and mass. The three main states of matter are solid, liquid and gas. Each state has unique properties based on how particles are arranged and how they move.

Now you know the basic🫶🏻

How does the kinetic theory of matter describe the behavior of particle in solids, liquids and gases?

• In solids, particles move freely. In liquids, particles vibrate. In gases, particles are fixed in place.

• In solids, particles vibrate in place. In liquids, particles move past each other. In gases, particles move rapidly and are spread apart.

• In solids, particles are far apart. In liquids, particles are close together. In gases, particles have no energy.

• In solids, particles are fixed. In liquids, particles move rapidly. In gases, particles do not move.

Answer explanation

The kinetic theory of matter explains that particles are in constant motion. In solids, particles have the least energy, vibrating in fixed position because of strong forces between them. In liquids, particles have more energy, allowing them to move past each other, which gives liquids fluidity. In gases, particles have the most energy, allowing them to move freely and occupy the whole volume of their container.

Quite challenging, don’t forget to memorize and understand the fact😊

Which of the following is an example of an element?

• Oxygen (O₂)

• Water (H₂O)

• Air

• Salt (NaCl)

Answer explanation

An element of pure substance made up of only one type of atom. Oxygen(O₂) is an example because it consists only oxygen atoms. Compounds like water(H₂O), are made up of two or more different elements chemically bonded together, and mixtures, like air, are physical combinations of different substances that are not chemically bonded.

Don’t forget, it only consist of one type of atom✨

Describe the phase of BC

• Increase in temperature

• No increase in temperature

• Heat energy released

• Heat energy absorbed

Answer explanation

No increase in temperature from B to C because heat energy absorbed by the particles is used to overcome the attraction force between the particles until solid changes to liquid.

This question always appear in your SPM, make sure to understand every phase✍🏻

This is a cooling curve of naphthalene, C₁₀H₈ .Based on the following answer below, which one is the compound that suitable to be used as a substitute for naphthalene and produce the same curve shape.

• Water

• Glucose (C₆H₁₂O₆)

• Salt (NaCl)

• Lauric acid (C₁₂H₂₄O₂)

Answer explanation

Lauric acid, C₁₂H₂₄O₂ is a type of fatty acid that can be obtained from coconuts. This acid is also suitable to be used as a substitute for naphthalene, C₁₀H₈ due to the similarities in their phase transition, particularly their melting and sublimation properties. They both have relatively low volatility and can exhibit similar thermal transition behaviors when exposed to heat, making lauric acid a reasonable substitute for naphthalene in experiments.

Sometimes it might be in your objective question, do memorize the answer📌

Mimi dries her clothes outside their house on a hot and sunny day. Name the process involved during clothes drying.

• Boiling

• Melting

• Evaporation

• Condensation

Answer explanation

The heat from the sun warms the water molecules in the clothes. As the temperature of the water increases, the water molecules gain energy. Water molecules at the surface of the clothes gain enough energy to break free from the liquid state and turn into water vapor ( gas ). This process is called evaporation. The moving air helps carry the water vapor away from the clothes, speeding up the drying process. As water vapor escapes into the atmosphere, more liquid water molecules at the surface of the clothe clothes can evaporate.

Now you know scientifically how your clothes dry🤩

State the subatomic particles in atoms of various element. (Answer using small letter)

Answer explanation

Atoms of all elements are made up of three main subatomic particles; protons, neutrons, electrons. These particles are arranged in a specific way within the atom, which defines the properties of the element. Protons defining the element, neutrons contributing to the mass and stability, and electrons influencing chemical behavior and bonding.

You’re in good path if you answer this correctly🤭

State the relative mass of electron.

Answer explanation

The mass of electron is much smaller than that of protons and neutrons. It has mass approximately 1/1840 of the mass proton. This is measured through precise experiments involving cathode ray tubes or electron microscopes, where the behavior of electrons in a field is used to determine their mass in comparison to protons.

Quite challenging because it’s a fraction, but electron is the only one in different number compare to neutron and proton✨

Najiha had learned about Bohr’s Atomic Model with her chemistry teacher and her teacher asked Najiha to create the Bohr’s Atomic Model atom with her own creativity. Based on the following picture below, which atom model should Najiha refer to?

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Answer explanation

Niel Bohr found out that the electrons in an atom move in shells around the nucleus and that nucleus contains protons. Hence, his Bohr’s Atomic Model is the model atom with shells and nucleus with positively charged in it .

Just memorize the main fact (what they have been discovered) by referring to your textbook . Sometimes it might appear as an objective question in your final exam.

Studies of atoms started since the introduction of atomic theory by Democritus, a Greek philosopher, around 500 B.C . After that, we know that the atomic structure model has been developed by many scientists’ efforts. Simply describe the development of the atomic structure model by Ernest Rutherford.

Answer explanation

Ernest Rutherford had discovered positively-charged particles called protons in the nucleus and almost the whole of atomic mass is concentrated in the nuclues. He also state that the electrons move outside the nucleon.

It’s a challenging question if you don’t look at your textbook right?🫣