Olympiad Test: Matter And Materials -1 - Class 4 MCQ

Volume refers to the amount of space that an object or substance occupies. It is a measure used to describe the three-dimensional space taken up by matter, applicable to both solids and liquids.

- Mercury: Mercury is a liquid at room temperature and is the only metal that is in liquid form under standard conditions.
- Water: Water is most commonly found in the liquid state at room temperature and atmospheric pressure.
- Petrol: Petrol, commonly used as a fuel, is a liquid under normal conditions.
- All of the above: Mercury, water, and petrol are substances that are typically in a liquid state under normal circumstances.

In solids, the molecules are tightly packed together in a regular pattern and have very little freedom to move around. This close packing results in strong intermolecular forces of attraction holding the molecules close together. The molecules in solids vibrate about fixed positions but do not move freely about the substance, unlike in liquids or gases. This structural rigidity and limited movement are indicative of the strong forces of attraction between the molecules in a solid state.

When you open a soda water bottle, the rapid release of bubbles you see is due to carbon dioxide. Soda water contains carbon dioxide that is dissolved under pressure. When the bottle is sealed, the pressure inside the bottle keeps the carbon dioxide dissolved in the liquid. As soon as the bottle is opened, the pressure inside the bottle decreases, allowing the dissolved carbon dioxide to escape from the solution in the form of gas bubbles. This release of gas is what you see as the bubbles in the soda.

Balloons can vary in volume because they are filled with air or another gas, and this volume can change depending on the pressure inside the balloon or the external atmospheric conditions. When a balloon is exposed to higher temperatures, the gas inside expands, increasing its volume. Conversely, cooling the balloon will decrease its volume. The other items listed (a teapot, a book, and a box) have fixed volumes under normal conditions and thus do not vary in volume like a balloon can.

Milk is a liquid, and like all liquids, it has a fixed volume but no fixed shape. This means that it will conform to the shape of its container but maintain a constant volume unless it is divided or removed from the container. Water vapor (A) is a gas and does not have a fixed volume or shape, adapting both its volume and shape to fit its container. Salt (B) and ice (D) are both solids and therefore have fixed shapes as well as fixed volumes under standard conditions.

- Water takes the shape of its container, indicating it has no definite shape.
- It can flow and spread to fill the container's bottom regardless of the container's shape, such as a cylinder, cube, or bowl.

• Honey is a liquid and not a solid. It has a thick, viscous consistency that flows and takes the shape of its container, distinguishing it from solids that retain a fixed shape.
• Plasticine (A), while malleable, is still considered a solid because it maintains its volume and can be shaped without flowing.
• Flour (B) is composed of fine particles but is categorized as a solid because these particles retain their volume and do not flow freely like a liquid.
• Cotton wool (C) is also a solid, consisting of fibrous material that maintains its volume and does not flow.

To separate sand from water:

- Filtration (Option C) is the correct method.
- Explanation: Filtration involves passing the mixture through a filter that retains the sand particles and allows the water to pass through.
- Process: The sand gets trapped in the filter while the water flows out, effectively separating the two components based on their particle size difference.
- Result: This process leaves behind the sand, giving you clean water.

Hydrogen is a gas at room temperature and pressure, and gases generally have much larger intermolecular spaces compared to solids and liquids. This is because the molecules in a gas are far apart and move freely, resulting in less dense arrangements. In contrast, solids like iron (A) and liquids like mercury (B) and water (C) have molecules that are much closer together, with very little intermolecular space. This difference in molecular arrangement is what allows gases to be compressible and expand to fill their containers, unlike solids and liquids.

When Sunil placed the salty water under sunlight, the water evaporated due to the heat, leaving behind the salt crystals. This is an example of evaporation, where liquid water turns into vapor, leaving the dissolved solids behind.

The diagram D depicts particles that are tightly packed together without any noticeable gaps, indicating a solid phase where particles are closely arranged and held together by strong intermolecular forces. This tightly packed arrangement is characteristic of solids, where the particles vibrate in fixed positions but do not move freely over large distances, unlike in liquids or gases.

The correct answer is D: The capacity of the water tank is 1 kg.

This statement is incorrectly written because "capacity" refers to the volume a container can hold, which should be measured in units of volume such as liters, milliliters, or cubic meters, not in kilograms, which is a unit of mass. Therefore, saying that the capacity of a water tank is "1 kg" mixes up measurements of mass and volume. The other options correctly use units of weight (kilograms and grams) for the mass of objects, and liters for the volume of a container.

Rubber, wood, it appears that the object shown in the figure is a plunger, typically used in plumbing. The image must show a wooden handle attached to a rubber cup, which aligns with the materials mentioned in option C. This makes sense as plungers commonly feature a flexible rubber cup that provides the necessary suction and a wooden handle for manual operation, making them effective for clearing clogs in drains. The other material combinations listed in options A, B, and D would not be typical for such an item.

Correct answer  is B. Metals can are opaque objects, which means they block light and do not allow it to pass through.

The correct answer is A: Has no definite volume.

Air, being a gas, does not have a definite volume. This means it will expand or compress to fill the volume of its container, unlike a liquid such as water, which maintains a definite volume regardless of the container it is in. Gases are compressible due to the large amount of space between their particles, allowing them to adapt their volume based on external pressure.

The other options, while also correct attributes of air, are not distinctive in comparing air to water, since both air and water have a definite mass (B), neither has a definite shape (C), and both occupy space (D). Option A specifically highlights a fundamental difference in the behavior of gases (like air) versus liquids (like water) regarding volume.

The correct answer is D: Solution.

A solution is a homogeneous mixture of two or more substances in which the substances are uniformly dispersed at the molecular level. This typically consists of a solute (the substance being dissolved) and a solvent (the substance in which the solute is dissolved). The other terms are related but have specific roles within the context of solutions:

• A mixture (A) can be homogeneous or heterogeneous but is a broader term that doesn't necessarily imply the molecular-level uniformity of a solution.
• A solute (B) is the component that is dissolved in another substance.
• A solvent (C) is the substance that dissolves the solute to form a solution.

The correct answer is A: Carbon dioxide.

Soda water, often referred to as carbonated water, primarily contains carbon dioxide that has been dissolved under pressure. When you open a bottle of soda water, the carbon dioxide escapes as bubbles, giving the water its fizzy characteristic. The other substances listed, such as oxygen (B), common salt (C), and wax (D), are not typically dissolved in soda water in significant amounts relevant to its common definition or use.

The correct answer is D: Condensation.

Condensation is the process in which a gas changes into a liquid. This occurs when a gas is cooled to its dew point or when it comes into contact with a cooler surface, causing the gas molecules to lose energy and come closer together to form a liquid. This is commonly observed when water vapor in the air turns into liquid water droplets, such as on the outside of a cold glass or in clouds forming in the atmosphere.

The other options refer to different phase changes:

• Melting (A) is the process by which a solid turns into a liquid.
• Solidification (B), also known as freezing, is the process in which a liquid turns into a solid.
• Evaporation (C) is the process where a liquid turns into a gas.

The correct answer is A: Sublimation.

- Sublimation is the process where a solid changes directly into a gas without passing through the liquid state.
- In this scenario, the naphthalene balls are undergoing sublimation because they are turning from a solid directly into a gas.
- This process is commonly observed in substances like naphthalene and dry ice (solid carbon dioxide).
- Sublimation is the opposite of deposition, where a gas changes directly into a solid.