2.1.1 Basic Concepts of Matter (Q&A)
Short Answer Questions
- What is matter?
Matter is anything that has mass and occupies space.
- What are the three states of matter?
The three states of matter are solid, liquid, and gas.
- How is matter classified?
Matter is classified as either an element or a compound.
- What are the three types of particles that make up matter?
Matter is made up of atoms, molecules, and ions.
- What is an atom?
An atom is the smallest particle of an element.
- What is a molecule?
A molecule consists of two or more atoms chemically bonded together.
- What is an ion?
An ion is a charged particle, either positive or negative.
- Define an element.
An element is a substance made entirely of one type of atom.
- Define a compound.
A compound is a substance consisting of two or more elements chemically bonded together.
- How are the particles arranged in a solid?
Particles in a solid are arranged in a very orderly and compact manner.
- Why do solids have a fixed shape?
Solids have strong attractive forces between particles, which keep them in fixed positions.
- Why can liquids flow but not be compressed easily?
Liquids have weaker attractive forces than solids, allowing particles to move past each other, but they are still closely packed.
- Why do gases not have a fixed shape or volume?
Gas particles are far apart and move freely, filling the container they are in.
- What happens to a solid during melting?
Particles gain kinetic energy, vibrate faster, and eventually overcome attractive forces, turning into a liquid.
- At what temperature does naphthalene melt?
Naphthalene melts at 80°C.
- What happens during boiling?
Particles gain enough energy to overcome attractive forces and escape as a gas.
- What is condensation?
Condensation is the process where a gas cools down and changes into a liquid.
- What is sublimation?
Sublimation is when a solid changes directly into a gas or vice versa without becoming a liquid.
- What happens to energy during freezing?
Energy is released, and particles move closer together to form a solid.
- Why does the temperature remain constant during melting?
The energy absorbed is used to overcome attractive forces between particles rather than increasing temperature.
Explanation Questions
- Explain why gases can be compressed easily.
Gas particles are far apart, allowing them to be pushed closer together when compressed.
- Why does a solid have a definite shape while a liquid does not?
Solid particles are tightly packed in fixed positions, whereas liquid particles move freely, taking the shape of their container.
- Explain why evaporation can occur at any temperature.
Some particles at the surface of a liquid have enough energy to escape into the gas phase even at lower temperatures.
- Why does naphthalene remain at 80°C during melting and freezing?
Energy is either absorbed to break forces or released as particles form bonds, maintaining a constant temperature.
- Describe the energy changes during boiling.
Heat energy is absorbed, increasing kinetic energy until particles gain enough energy to break free as gas.
- Why do solids have the least energy content among the three states?
Solid particles are closely packed and only vibrate, requiring minimal energy.
- Explain why condensation occurs when a gas is cooled.
Cooling reduces kinetic energy, allowing attractive forces to bring particles closer together into a liquid.
- Why do liquids take the shape of their container but solids do not?
Liquid particles can move freely, while solid particles remain in fixed positions.
- Why do gases have the highest energy content?
Gas particles move freely at high speeds, requiring more energy.
- Explain the role of kinetic energy in state changes.
Kinetic energy increases or decreases, affecting particle movement and overcoming attractive forces to change states.