Understanding Intermolecular Forces and Matter Concepts

1. Would you consider the gas coming out of our lungs as a matter? (a) no, it has only mass but does not occupy space (b) no, because it cannot be seen (c) yes, because even though it doesn’t have mass, it occupies space (d) yes, because it has both mass and occupies space

No, it has only mass but does not occupy space

No, because it cannot be seen

Yes, because even though it doesn’t have mass, it occupies space

Yes, because it has both mass and occupies space

Gas is considered a form of matter because it possesses both mass and occupies space. Although gases may be invisible and less dense than solids or liquids, they still consist of particles that have mass. These particles move freely and fill the volume of their container, demonstrating that they occupy space. Therefore, the properties of gases align with the definition of matter, which is anything that has mass and volume.

Explanation

Gas is considered a form of matter because it possesses both mass and occupies space. Although gases may be invisible and less dense than solids or liquids, they still consist of particles that have mass. These particles move freely and fill the volume of their container, demonstrating that they occupy space. Therefore, the properties of gases align with the definition of matter, which is anything that has mass and volume.

2. Two adjacent water molecules are labelled as 1 and 2. We are pouring water from a jug into the glass. What kind of intermolecular force is acting between the two water molecules? (a) attractive force (b) repulsive force (c) no force is acting between them (d) information insufficient

Attractive force

Repulsive force

No force is acting between them

Information insufficient

Water molecules are polar, meaning they have a partial positive charge on one side and a partial negative charge on the other. This polarity leads to hydrogen bonding, an attractive intermolecular force that occurs between the positively charged hydrogen atoms of one water molecule and the negatively charged oxygen atoms of another. These attractive forces help to hold the water molecules together, contributing to water's unique properties, such as cohesion and surface tension.

Explanation

Water molecules are polar, meaning they have a partial positive charge on one side and a partial negative charge on the other. This polarity leads to hydrogen bonding, an attractive intermolecular force that occurs between the positively charged hydrogen atoms of one water molecule and the negatively charged oxygen atoms of another. These attractive forces help to hold the water molecules together, contributing to water's unique properties, such as cohesion and surface tension.

3. In August 2010, in Delaware Bay, many fish were reported dead. Research found that a lack of dissolved oxygen in the water led to these deaths. Where is this dissolved oxygen present in water? (a) inside the atoms of water molecules (b) in the spaces between water molecules (c) in the spaces between the atoms of water molecules (d) a gas (oxygen) cannot be dissolved in water

Inside the atoms of water molecules

In the spaces between water molecules

In the spaces between the atoms of water molecules

A gas (oxygen) cannot be dissolved in water

Dissolved oxygen in water is found in the spaces between water molecules, where it exists as a gas that has been absorbed into the liquid. This oxygen is critical for aquatic life, as fish and other organisms rely on it for respiration. When oxygen levels drop, such as in the case of the fish deaths in Delaware Bay, it can lead to hypoxia, resulting in significant harm to marine ecosystems. Thus, understanding the location of dissolved oxygen helps explain its vital role in maintaining healthy aquatic environments.

Explanation

Dissolved oxygen in water is found in the spaces between water molecules, where it exists as a gas that has been absorbed into the liquid. This oxygen is critical for aquatic life, as fish and other organisms rely on it for respiration. When oxygen levels drop, such as in the case of the fish deaths in Delaware Bay, it can lead to hypoxia, resulting in significant harm to marine ecosystems. Thus, understanding the location of dissolved oxygen helps explain its vital role in maintaining healthy aquatic environments.

4. There is a burning incense stick (agarbatti) in a room. Three students are discussing what will happen to its smoke in different conditions – Arpit – if there is no wind in the room, the smoke will never reach the other corner of the room. Swapnil – even if there is no wind, the particles of smoke will spread across the room. Rutvik – the particles of smoke will never spread in the room, irrespective of the wind. Who is/are correct? (a) only Arpit (b) only Swapnil (c) only Rutvik (d) only Arpit and Rutvik

Only Arpit

Only Swapnil

Only Rutvik

Only Arpit and Rutvik

In a room with no wind, smoke from a burning incense stick will still spread due to diffusion, a natural process where particles move from areas of higher concentration to lower concentration. Swapnil correctly states that the smoke particles will disperse throughout the room over time, even in still air. Arpit's assertion that the smoke will never reach the other corner is incorrect, as diffusion allows for gradual movement, while Rutvik's claim that the particles will never spread is also false. Thus, only Swapnil's statement aligns with the principles of gas behavior.

Explanation

In a room with no wind, smoke from a burning incense stick will still spread due to diffusion, a natural process where particles move from areas of higher concentration to lower concentration. Swapnil correctly states that the smoke particles will disperse throughout the room over time, even in still air. Arpit's assertion that the smoke will never reach the other corner is incorrect, as diffusion allows for gradual movement, while Rutvik's claim that the particles will never spread is also false. Thus, only Swapnil's statement aligns with the principles of gas behavior.