1.
What is the first step in a scientific investigation?
Correct Answer
C. Identifiying the problem
Explanation
The first step in a scientific investigation is identifying the problem. Before any research or experimentation can take place, scientists must clearly define the problem they wish to solve or the question they want to answer. This step helps to focus the investigation and guide the subsequent steps of making observations, forming a hypothesis, and planning an experiment. Identifying the problem is crucial in ensuring that the scientific investigation is purposeful and targeted towards finding a solution or gaining new knowledge.
2.
Which substance is an element?
Correct Answer
C. Carbon
Explanation
Carbon is an element because it is a pure substance that cannot be broken down into simpler substances by chemical means. It is composed of only one type of atom, which is carbon. Air is a mixture of different gases, Stim is not a known substance, and Napthalene is a compound made up of carbon and hydrogen atoms. Therefore, carbon is the only option that fits the definition of an element.
3.
Which of the following substances is made up of atoms?
Correct Answer
A. Argon
Explanation
Argon is a chemical element with the symbol Ar and atomic number 18. It is a noble gas and exists as individual atoms. Nitrogen, chlorine, and ammonia are all compounds that consist of molecules made up of multiple atoms bonded together. However, Argon is the only substance listed that is made up of individual atoms.
4.
Which substance is an ionic compound?
Correct Answer
D. Magnesium oxide
Explanation
Magnesium oxide is an ionic compound because it is formed by the transfer of electrons between magnesium and oxygen atoms. Magnesium has a tendency to lose two electrons, becoming a positively charged ion (Mg2+), while oxygen has a tendency to gain two electrons, becoming a negatively charged ion (O2-). The resulting attraction between these oppositely charged ions forms the ionic bond in magnesium oxide. In contrast, ethanol, sulphur dioxide, and tetrachloromethane are covalent compounds, where electrons are shared between atoms rather than transferred.
5.
Which of the following substances contain molecules?
Correct Answer
B. Ethanol
Explanation
Ethanol contains molecules because it is an organic compound composed of carbon, hydrogen, and oxygen atoms. Molecules are formed when atoms bond together, and in the case of ethanol, the carbon, hydrogen, and oxygen atoms combine to form the molecule of ethanol. Zinc, sodium chloride, and magnesium oxide, on the other hand, do not contain molecules. Zinc is an element, and elements exist as individual atoms. Sodium chloride and magnesium oxide are both compounds, but they are formed by the attraction of ions, not molecules.
6.
An enclosed cylinder is filled with helium atoms. Which diagram shows the arrangement of the helium atoms?
Correct Answer
D. D
Explanation
Diagram D shows the arrangement of the helium atoms in an enclosed cylinder. The helium atoms are evenly distributed throughout the cylinder, with no specific pattern or arrangement. This is because helium atoms are small and have weak intermolecular forces, allowing them to move freely and occupy the entire space within the cylinder. Therefore, diagram D accurately represents the arrangement of helium atoms in an enclosed cylinder.
7.
Which of the following shows the correct type of particle for each substance?
Correct Answer
B. B
Explanation
The correct answer is B because it shows the correct type of particle for each substance.
8.
The diagram shows the partivles arrangement of a substance at room temperature.
What is the substance?
Correct Answer
B. Helium
Explanation
The diagram shows the particles arranged in a random and dispersed manner. This indicates that the substance is in a gaseous state at room temperature. Among the given options, only Helium is a gas at room temperature, making it the correct answer.
9.
The diagram shows the arrangement of partivles in a substance at room temperature.
This arrangement of partivles can be found in
Correct Answer
C. Oxygen
Explanation
The diagram shows the arrangement of particles in a substance at room temperature. Oxygen is the correct answer because the diagram represents the arrangement of particles in oxygen at room temperature.
10.
Figure 11 shows the arrangement of particles found in four substances as named.
Which pairs of the arrangement of partivles and the name of the substances are paired correctly?
Correct Answer
D. III and IV only
Explanation
The correct answer is III and IV only. This is because in Figure 11, substance III shows a regular and orderly arrangement of particles, which is characteristic of a crystalline solid. Substance IV, on the other hand, shows a random and disordered arrangement of particles, which is characteristic of a gas. Therefore, these pairs are correctly matched.
11.
Which of the following diagram represents magnesium oxide?
Correct Answer
C. C
12.
The following statements are about diffusion.
* The tiny particles are discrete
* The tiny particles move randomly by themselves
Which of the following situations are explained by the statements above?
I bromine gas mixing with air
II aqueous copper(II) sulphate moving through a gel
III melting of lead(II) bromide
IV combustion of magnesium in air
Correct Answer
A. I and II
Explanation
The statements about diffusion explain situations I and II because both involve the movement of tiny particles (bromine gas and aqueous copper(II) sulphate) in a random and discrete manner.
13.
Which of the following processes, proved the kinetic theory of matter?
Correct Answer
A. Diffusion
Explanation
Diffusion is the process by which particles move from an area of high concentration to an area of low concentration. This process is a direct result of the kinetic theory of matter, which states that all particles are in constant motion. Diffusion occurs because the particles are constantly moving and colliding with each other, causing them to spread out and distribute evenly. Therefore, diffusion is a process that provides evidence for the kinetic theory of matter.
14.
A sample of carbon dioxide gas is cooled. Which of the following is true about the velocity and the size of its particles?
Correct Answer
D. D
Explanation
When a sample of carbon dioxide gas is cooled, the velocity of its particles decreases. As the temperature decreases, the kinetic energy of the particles decreases, causing them to move slower. However, the size of the particles remains the same. Cooling the gas does not affect the size of the individual particles, only their movement. Therefore, option D is the correct answer.
15.
Diagram 1 shows an experiment to study the partivles theory of matter.
After 30 minutes, the water turns purple. What is the process occur in the experiment shown in the diagram 1?
Correct Answer
C. Diffusion process
Explanation
The process occurring in the experiment shown in Diagram 1 is diffusion. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. In this case, the purple color of the water indicates that a substance has been added to it, and over time, the particles of this substance spread out evenly throughout the water, resulting in the purple color diffusing throughout the entire solution.
16.
The diagram shows an experiment to study the particle theory of matter.
Which of the following is the best explanation of the observation in the experiment?
Correct Answer
C. Particles in copper(II) sulpHate are minute and dicrete
Explanation
The observation in the experiment can be explained by the fact that the particles in copper(II) sulphate are minute and discrete. This means that the particles are very small and separate from each other. As a result, when the copper(II) sulphate is added to the agar, the particles can easily mix and dissolve in the agar. The small size and discrete nature of the particles allow for efficient mixing and dissolution.
17.
Diagram 2 shows the set up of apparatus to investigate the diffusion in a liquid. After a few hours, the whole test tube of water becomes purple in colour.
Which of the following statements explain the observation?
Correct Answer
C. Matter is made up of partivles that are moving randomly
Explanation
The observation that the whole test tube of water becomes purple in color suggests that the particles in potassium manganate(VII) are moving randomly. This is because diffusion is the movement of particles from an area of high concentration to an area of low concentration, and the fact that the color has spread evenly throughout the water indicates that the particles are moving randomly and spreading out uniformly.
18.
The diagram shows the aparatus set - up to investigate Process X.
What is Process X?
Correct Answer
A. Diffusion
Explanation
The diagram shows an apparatus set up to investigate Process X. Diffusion is the movement of particles from an area of high concentration to an area of low concentration. In the given diagram, there is a concentration gradient indicated by the arrows, suggesting the movement of particles from one side to the other. This is characteristic of diffusion, making it the correct answer.
19.
Figure 6 shows an experiment to compare the rate of diffusion between ammonia and yhdrogen chloride gases.
The bigger the mass of a particle, the slower the velocity of the particle.
Based on the above statement, where will the white fumes of ammonium chloride first formed?
Correct Answer
C. R
Explanation
According to the statement, the bigger the mass of a particle, the slower the velocity of the particle. In the experiment, ammonia and hydrogen chloride gases are being compared for their rate of diffusion. Ammonium chloride is formed when ammonia gas (NH3) reacts with hydrogen chloride gas (HCl). Since ammonia has a smaller molar mass than hydrogen chloride, the ammonia particles will have a higher velocity and will diffuse faster. Therefore, the white fumes of ammonium chloride will first be formed at the location where the ammonia gas is present, which is at point R.
20.
Which of the following substances sublimes when heated?
Correct Answer
A. Ammonium chloride
Explanation
Ammonium chloride is the substance that sublimes when heated. Sublimation is the process in which a solid directly turns into a gas without passing through the liquid state. When heated, ammonium chloride undergoes sublimation, meaning it goes from a solid directly to a gas, without melting into a liquid first. This is due to the compound's unique chemical properties and its ability to vaporize at a relatively low temperature.
21.
Which of these substances will sublimate when heated?
Correct Answer
B. Iodine
Explanation
Iodine will sublimate when heated because it undergoes a phase change directly from a solid to a gas without passing through the liquid phase. Sublimation occurs when the vapor pressure of a solid exceeds atmospheric pressure at a given temperature, causing the solid to transform into a gas. In the case of iodine, heating it causes the solid iodine crystals to vaporize and form a purple-colored gas.
22.
Which of the following solids changes to gaseous state when it is heated?
Correct Answer
C. Ammonium chloride
Explanation
Ammonium chloride changes to the gaseous state when it is heated. This is because ammonium chloride is a compound that undergoes sublimation, which means it directly converts from a solid to a gas without passing through a liquid state. When heated, the strong ionic bonds between the ammonium (NH4+) and chloride (Cl-) ions break, and the compound vaporizes into ammonia gas (NH3) and hydrogen chloride gas (HCl). This process is endothermic, meaning it requires energy input to occur.
23.
The diagram shows the change of state of matter.
Which of the following is process X?
Correct Answer
B. Boiling
Explanation
The diagram shows the process of boiling, which is the change of state from a liquid to a gas. This is evident from the upward arrows indicating the release of gas particles. Boiling occurs when a substance is heated to its boiling point, causing the liquid particles to gain enough energy to overcome the intermolecular forces and escape into the gas phase. Therefore, process X in the diagram is boiling.
24.
Diagram 1 shows the inter-conversion of the states of matter of a substance.
Which inter-conversion involves the release of energy?
Correct Answer
A. Steam ---> ice
Explanation
When steam converts into ice, energy is released. This is because the process of condensation occurs, where the steam loses heat energy and transforms into a solid state. This release of energy is due to the change in the molecular arrangement and the formation of stronger intermolecular forces in the ice.
25.
Diagram 1 shows the inter conversion of water, steam and ice. In which conversion do the molecule lose speed?
Correct Answer
D. Steam ---> ice
Explanation
When steam converts into ice, the molecules lose speed. This is because steam is in the gaseous state and the molecules are moving rapidly and freely. However, when steam cools down and condenses into ice, the molecules slow down and become tightly packed. Therefore, the conversion from steam to ice involves a decrease in molecular speed.
26.
Diagram 1 shows the partivles arrangement for the change of state of matter. Which of the following is Process X?
Correct Answer
B. Sublimation
Explanation
Process X is sublimation. Sublimation is the process in which a solid directly changes into a gas without going through the liquid state. In the given diagram, it shows particles arranged in a solid state on one side and in a gaseous state on the other side, indicating the direct transition from solid to gas, which is characteristic of sublimation.
27.
The melting point of substance Z is and its boiling point is What is the physical state of substance Z at room temperature?
Correct Answer
C. Liquid
28.
The melting point and boiling point of substance M is respectively. The physical state of substance M at room temperature is
Correct Answer
A. Gas
Explanation
Based on the information given, substance M has a melting point and boiling point that are not specified. However, it is stated that the physical state of substance M at room temperature is gas. This suggests that substance M has a low melting point and boiling point, causing it to exist as a gas at room temperature.
29.
Table 2 shows the melting and boiling points of substances V, W, X dan Y.
Which of the following substances is in liquid from at room temperature?
Correct Answer
D. Y
Explanation
Substance Y is in liquid form at room temperature because it has a low melting point and boiling point compared to substances V, W, and X. This indicates that Y can exist as a liquid at the average temperature of a room, while the other substances would be in a solid or gaseous state.
30.
The table shows the melting point and boiling point of foru substances W, X, Y and Z
Which of the substances is a liquid at
Correct Answer
D. Z
Explanation
Based on the information provided in the table, substance Z is a liquid at a certain temperature. This can be inferred because the table shows the melting point and boiling point of the substances, and Z is the only substance that has a boiling point but no melting point listed. This indicates that Z exists as a liquid at temperatures above its boiling point.
31.
The table shows the melting points of substances P, Q, R and S.
Which of the following substances is a solid at
Correct Answer
A. P
Explanation
Based on the given information, substance P is a solid at its melting point.
32.
Table 2 shows the melting point and boiling points of fice compounds J, K, L, M and N. Which substances exists as a liquid at toom temperature?
Correct Answer
C. K and L only
Explanation
Substances K and L exist as liquids at room temperature because their boiling points are below room temperature. J has a higher boiling point, so it exists as a solid at room temperature. M and N have even higher boiling points, so they exist as gases at room temperature.
33.
Diagram 6 shows the cooling curve of liquid Y.
Which statement can be deduced from Diagram 6.
Correct Answer
B. The freezing point of Y is 70 degree celcius
Explanation
The correct answer can be deduced from Diagram 6 because at the freezing point of a substance, the temperature remains constant as the substance changes from a liquid to a solid. In Diagram 6, there is a horizontal line at 70 degrees Celsius, indicating that Y is freezing and transitioning from a liquid to a solid at this temperature.
34.
The diagram shows the cooling of liquid napthalene.
Which of the followings shows the physical states at X and Y.
Correct Answer
D. D
Explanation
The correct answer is D because at point X, the liquid napthalene is still in its liquid state, as indicated by the curved line. At point Y, the liquid napthalene has cooled down enough to solidify, as indicated by the flat line. Therefore, the physical states at X and Y are liquid and solid, respectively.
35.
The diagram shows a graph of temperature against time for the heating of substance X.
Which of the following is true about substance X at the sixth minute?
Correct Answer
D. Some molecules are closely packed while some molecules move freely
Explanation
Based on the given graph, the temperature of substance X is increasing over time. This indicates that the substance is being heated. At the sixth minute, the temperature is still rising, suggesting that the heating process is ongoing. Therefore, it can be inferred that some molecules of substance X are closely packed together, while others are moving freely. This is because the increasing temperature causes the molecules to gain kinetic energy and move more rapidly, but not all molecules have reached the same level of energy distribution, resulting in some being closely packed while others move freely.
36.
Which of the following scientists discovered proton?
Correct Answer
B. J. J Thomson
Explanation
J.J. Thomson discovered the proton. He conducted experiments with cathode rays and discovered that they were made up of negatively charged particles, which he called electrons. Thomson proposed the "plum pudding" model of the atom, where the electrons were embedded in a positively charged "pudding." Later, Ernest Rutherford conducted the gold foil experiment and discovered the nucleus, which contains positively charged particles called protons. However, it was J.J. Thomson who first discovered the existence of protons through his work on cathode rays.
37.
Which of the following statements is true about atomic model proposed by Ernest Rutherford?
Correct Answer
D. The nucleus of the atom contains proton.
Explanation
The correct answer is "The nucleus of the atom contains proton." This statement is true because Ernest Rutherford's atomic model proposed that the atom consists of a small, dense, positively charged nucleus at the center, which contains protons. The electrons, on the other hand, move in shells or orbits around the nucleus. This model is known as the Rutherford model or the planetary model of the atom.
38.
The following tatements refer to the contributions of a scientist in the development of ideas about atomic structure.
* Discovered proton
* Most of the mass of the atoms is in the nucleus
* The electrons move in empty space
Who was the scientist?
Correct Answer
D. Ernest Rutherford
Explanation
Ernest Rutherford is the correct answer because he made significant contributions to the understanding of atomic structure. He discovered the existence of the proton, which is a subatomic particle found in the nucleus of an atom. Rutherford also proposed the nuclear model of the atom, which states that most of the mass of an atom is concentrated in the nucleus. He conducted the famous gold foil experiment, which led to the discovery that the electrons move in empty space around the nucleus.
39.
The diagram shows a model of an atom.
Who introduced this model?
Correct Answer
C. J.J. Thompson
Explanation
J.J. Thompson introduced the model of an atom.
40.
Diagram 1 shows the atomic model of an atom.
Which of the following scentists suggested the model?
Correct Answer
B. James Chadwick
Explanation
James Chadwick suggested the atomic model shown in Diagram 1.
41.
The diagram shows a model of an atom.
Who introduced this model?
Correct Answer
A. Neils Bohr
Explanation
Niels Bohr introduced the model of the atom shown in the diagram. His model, known as the Bohr model, proposed that electrons orbit the nucleus in specific energy levels or shells. This model was a significant advancement in understanding atomic structure and helped explain the stability of atoms.
42.
Diagram 3 shows a model of an atom.
Which of the following is true of the atomic model?
I Proposed by Neil Bohr
II Was built based on the existence of the neutron
III Shows that electrons move in shells around the nucleus
IV Discovered through the bombardment experiment of alpha particles on gold foil
Correct Answer
A. I and III only
Explanation
The atomic model shown in Diagram 3 proposes that electrons move in shells around the nucleus. This idea was proposed by Neil Bohr, making statement I true. Statement II is false because the existence of the neutron was not the basis for this atomic model. Statement III is true because the diagram clearly shows the electrons arranged in different shells around the nucleus. Statement IV is false because the atomic model was not discovered through the bombardment experiment of alpha particles on gold foil. Therefore, the correct answer is I and III only.
43.
Which of the following atomic models was proposed by Ernest Rutherford?
Correct Answer
C. The atom contains a nucleus surrounded by electrons moving at tandom
Explanation
Ernest Rutherford proposed the atomic model in which the atom contains a nucleus surrounded by electrons moving at random. In his famous gold foil experiment, Rutherford discovered that most of the mass and positive charge of an atom is concentrated in a small, dense nucleus at the center. The electrons, on the other hand, are located outside the nucleus and move in random orbits. This model revolutionized our understanding of atomic structure and laid the foundation for further advancements in the field of atomic physics.
44.
The nucleus of an atom contains
Correct Answer
C. Both protons and neutrons
Explanation
The nucleus of an atom contains both protons and neutrons. Protons have a positive charge and are responsible for determining the atomic number of an element. Neutrons have no charge and help stabilize the nucleus by balancing the repulsive forces between protons. Electrons, on the other hand, are found outside the nucleus in electron shells and are negatively charged. Therefore, the correct answer is both protons and neutrons.
45.
What are the symbols of the elements of cromium, copper, manganese and pottasium?
Correct Answer
D. D
Explanation
The correct answer is D because the symbols for the elements chromium, copper, manganese, and potassium are Cr, Cu, Mn, and K, respectively.
46.
Atom of oxygen-18 has 8 electrons. How many neutrons does an atom of oxygen-18 contains?
Correct Answer
C. 10
Explanation
An atom of oxygen-18 has 8 electrons, which is the same as the number of protons in the nucleus. Since the atomic number of oxygen is 8, this means that oxygen-18 has 8 protons. The atomic mass of oxygen-18 is 18, so to find the number of neutrons, we subtract the number of protons from the atomic mass. Therefore, an atom of oxygen-18 contains 10 neutrons.
47.
Which of the following statements is true about subatomic particles?
Correct Answer
B. Protons and neutrons are found in the nucleus of an atom.
Explanation
The statement that "protons and neutrons are found in the nucleus of an atom" is true. Protons and neutrons are subatomic particles that are located in the nucleus of an atom, which is the central region of the atom. The nucleus contains most of the mass of the atom, and the protons have a positive charge while the neutrons have no charge. This statement accurately describes the location and nature of these subatomic particles within an atom.
48.
Diagram shows the electron arrangement for the ion. An atom of element J contains 12 neutrons.
What is the nucleon number of element J?
Correct Answer
D. 25
49.
Atom X has a proton number 9 and the nucleon number is 19. Which of the following symbols is for atom X?
Correct Answer
B. B
Explanation
The correct symbol for atom X is B. The proton number of an atom represents the number of protons in its nucleus, which in this case is 9. The nucleon number, also known as the mass number, represents the total number of protons and neutrons in the nucleus, which in this case is 19. Therefore, the symbol for atom X should have 9 protons and 19 nucleons, which is represented by option B.
50.
Diagram shows the symbols for chlorine atom.
Which of the following is true based on the symbols in diagram1.
Correct Answer
A. A
Explanation
Based on the symbols in the diagram, we can see that the symbol for chlorine atom is Cl. Therefore, it is true that the symbol for chlorine atom is Cl.