Intej Chemistry Department (Diagnostic 1)

The relative formula mass of a compound is calculated by adding up the relative atomic masses of all the atoms in the formula. In this case, the formula for aluminium sulphate is Al2(SO4)3. The relative atomic mass of Al is 27, the relative atomic mass of S is 32, and the relative atomic mass of O is 16. Therefore, the relative formula mass can be calculated as (2 * 27) + (3 * (32 + (4 * 16))) = 54 + 3 * (32 + 64) = 54 + 3 * 96 = 54 + 288 = 342.

Carbon-14 is used in archaeology because it is a radioactive isotope of carbon that is present in the atmosphere and absorbed by living organisms. When an organism dies, it no longer takes in carbon-14, and the amount of carbon-14 in its remains gradually decreases over time through radioactive decay. By measuring the remaining amount of carbon-14 in archaeological artifacts, scientists can determine their age and gain insights into past civilizations and events.

The number of molecules in 1 mole of ammonia, NH3, is equal to Avogadro's constant, which is 6.02 x 10^23 mol-1. This constant represents the number of particles (atoms, molecules, or ions) in one mole of a substance. In this case, it refers to the number of NH3 molecules in 1 mole of ammonia.

The electron arrangement for element X is 2.1, meaning it has 2 electrons in the first energy level and 1 electron in the second energy level. The electron arrangement for element Y is 2.8.7, meaning it has 2 electrons in the first energy level, 8 electrons in the second energy level, and 7 electrons in the third energy level.

The relative molecular mass of a compound is the sum of the relative atomic masses of all the atoms in the compound. In this case, the compound has two sodium atoms (Na) and two X atoms, along with three oxygen atoms (O). Given that the relative atomic mass of sodium is 23 and the relative atomic mass of oxygen is 16, we can calculate the relative molecular mass as follows: (2 * 23) + (2 * X) + (3 * 16) = 158. Simplifying the equation, we get 46 + 2X + 48 = 158. Solving for X, we find that X = 32. Therefore, the relative atomic mass of element X is 32.

Potassium is the correct answer because it is an alkali metal that reacts vigorously with oxygen. When potassium is burned in a gas jar filled with oxygen, it produces a very bright purplish flame. The flame color is due to the excitation of electrons in the potassium atoms. The reaction also produces a white residue, which is potassium oxide (K2O).

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Beryllium has an atomic number of 4, which means it has 4 electrons. The diagram shows that there are 2 electrons in the outermost shell, which is also known as the valence shell. Therefore, the number of valence electrons in a beryllium atom is 2.

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The relative atomic mass of element X is 48. This can be determined by comparing the mass of two atoms of X to that of three atoms of sulfur. Since the relative atomic mass of sulfur is 32, and the mass of three sulfur atoms is equal to the mass of two atoms of X, we can set up the equation (32 * 3) / 2 = 48. Therefore, the relative atomic mass of element X is 48.

The electron arrangement of T is 2.8.2. This means that T has a total of 12 electrons. The first energy level can hold a maximum of 2 electrons, the second energy level can hold a maximum of 8 electrons, and the third energy level can hold a maximum of 8 electrons. Since T has 12 electrons, it fills the first energy level with 2 electrons, the second energy level with 8 electrons, and the third energy level with 2 electrons.

The electron arrangement of atom A is 2.1. This means that atom A has 2 electrons in its first energy level and 1 electron in its second energy level.

The oxide ion has more electrons than the oxygen atom. An atom of oxygen typically has 8 electrons, but when it gains two additional electrons, it becomes an oxide ion. This extra electron gives the oxide ion a negative charge, making it different from a regular oxygen atom.

Element X reacts with element Y to form a compound with the formula XY. This means that when element X and element Y combine, they create a compound in which the atoms of X and Y are bonded together, forming a molecule with the formula XY.

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The correct answer is I and IV only. This means that only statements I and IV are true about the curve. The explanation for this answer can be found by analyzing the information given in the question and the diagram. However, since the question and diagram are not provided, it is not possible to generate a specific explanation for this answer.

The fact that the compound formed by elements E and G can conduct electricity in the molten state suggests that it contains charged particles (ions) that are free to move and carry electric current. This indicates that the compound is likely to be an ionic compound, where the atoms of element E have given away electrons to the atoms of element G, forming positive and negative ions. In the molten state, these ions are free to move and conduct electricity.

As you move across Period 3 of the periodic table, the atomic size decreases because the proton number increases. The atomic size is determined by the balance between the attractive force of the protons in the nucleus and the repulsive force of the electrons in the electron cloud. As the number of protons increases, the attractive force becomes stronger, pulling the electrons closer to the nucleus and reducing the atomic size. Therefore, the increase in proton number is the reason for the decreasing atomic size across Period 3.

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Based on the given information, element Q is most probably iron.

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Both isotopes have the same chemical properties because chemical properties are determined by the number and arrangement of electrons in an atom, not by the number of protons or neutrons. Isotopes of an element have the same number of protons and electrons, so their chemical properties remain the same. The number of neutrons does not affect the chemical behavior of an atom.

Carbon dioxide gas (CO2) has the biggest volume at room temperature and pressure because it has the highest molar mass among the given gases. Molar mass is directly proportional to the volume occupied by a gas at a given temperature and pressure. Since CO2 has the highest molar mass of 44 g/mol, it will have the largest volume compared to the other gases with lower molar masses.

The bulb lights up when potassium iodide solution is used because potassium iodide is an electrolyte. Electrolytes are substances that conduct electricity when dissolved in water or in a molten state. When potassium iodide is dissolved in water, it dissociates into potassium ions (K+) and iodide ions (I-), which are free to move and carry electric charge. This movement of ions allows the flow of electric current, causing the bulb to light up.

Chlorine is a Group 17 element, also known as a halogen. Halogens are highly reactive and tend to form compounds with other elements. Chlorine reacts with potassium to form potassium chloride, which is a common salt. This reaction is representative of the reactivity of chlorine and its ability to form compounds with other elements.

The observation that the whole test tube of water becomes purple in color indicates that the particles of potassium manganate(VII) are spreading out and mixing with the water particles. This can only happen if the particles are moving randomly, as stated in the correct answer. If the particles were moving uniformly or if potassium manganate(VII) was denser than water, the color would not have spread throughout the entire test tube. Additionally, the speed of the particles is not relevant to the observation.

Ammonium chloride changes to a gaseous state when it is heated. This is because ammonium chloride is a compound that undergoes sublimation, which is the process of transitioning directly from a solid to a gas without passing through the liquid state. When heated, the solid ammonium chloride sublimes and turns into a gas, without forming a liquid phase in between.

When an atom receives an electron, it gains a negative charge because the number of electrons is now greater than the number of protons. This negatively charged atom is called an anion. Anions are formed when non-metal atoms gain electrons to achieve a stable electron configuration. Therefore, the correct answer is "an anion."

The element with symbol Nw has eight outer electrons, which indicates that it belongs to Group 18 of the periodic table, also known as the noble gases. Noble gases are known for their stable electron configurations and do not readily form compounds with other elements. Therefore, Nw exists as monoatomic, meaning it exists as individual atoms rather than forming compounds or molecules.

The statement that is correct about elements X, Y, and Z is II and IV only. Atomic size generally decreases from left to right across a period, so the atomic size decreases from Y, Z, and X. Electronegativity also generally increases from left to right across a period, so the electronegativity increases from Y, Z, and X. The other statements, such as the proton number and the melting points, are not necessarily related to the acidic, basic, or amphoteric nature of the oxides and cannot be determined from the given information.

The statement "5 moles of Z have the same mass as 1 mole of Y" is true because the relative atomic mass of Y is 5 times greater than that of Z. Therefore, in order to have the same mass, 5 moles of Z would be needed to equal the mass of 1 mole of Y.

Based on the given information, the melting point of substance Z is -112oC and its boiling point is 78oC. Room temperature is typically around 20-25oC. Since the boiling point is higher than room temperature and the melting point is lower than room temperature, substance Z would be in a liquid state at room temperature.

Based on the information given in Table 2, the nucleon number and the number of neutrons are not relevant factors in determining reactivity or electropositivity. The fact that G is more reactive than L cannot be determined from the information given, so the answer is not supported. Therefore, the correct answer cannot be determined based on the given information.

The formula for the compound formed between carbon and element Z would be CZ2.

Caesium is denser than sodium because it is located below sodium in Group 1 of the periodic table, meaning it has more mass packed into the same volume. Caesium is more reactive than sodium because it is further down the group and has a larger atomic radius, making it easier for it to lose an electron and form positive ions. Caesium atom is bigger than sodium atom because as you move down a group in the periodic table, the atomic radius increases. Caesium is more electropositive than sodium because it has a lower ionization energy, meaning it is more likely to lose an electron and form positive ions.

The formula of the phosphate of metal M is MPO4. This is because the valency of M in MBr3 is 3, and the valency of PO4 in Na3PO4 is also 3. Therefore, the metal M combines with the phosphate group (PO4) to form MPO4.

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The nucleon number of an atom is equal to the sum of its protons and neutrons. Since Ion W3+ has 14 neutrons, we can deduce that it also has 14 protons. Therefore, the nucleon number of an atom of element W is 27 (14 protons + 14 neutrons).

The ion X2+ has a charge of +2, which means it has lost two electrons. Since the ion has a nucleon number of 40 and contains 20 neutrons, we can determine that the ion has 20 protons. This is because the nucleon number is equal to the sum of the protons and neutrons in an atom. Therefore, the statement "The ion X2+ contains 20 protons" is true.