Science Q3 part 2

Chemical Change and Heat Transfer

• A chemical change is a transformation resulting in the formation of new substances with different properties.
• An exothermic change involves heat moving out from the system into the surroundings.

Law of Conservation of Mass

• The Law of Conservation of Mass states that the total mass remains constant in a chemical reaction; matter is neither created nor destroyed.

Substances and Chemical Changes

• Substances that are broken down by a chemical change are referred to as reactants.

States of Matter

• The three main states of matter: solid, liquid, gas. Plasma is often considered a fourth state, but some lists may exclude it.
• Changes in states of matter are primarily caused by temperature and pressure variations.

Effect of Temperature on Solids

• As temperature increases, solids typically expand and can transition to a liquid state through melting.

Kinetic Molecular Theory

• According to Kinetic Molecular Theory, the main reason for the volume that matter occupies is the space between particles and their motion.

Pure Substances

• A pure substance contains only one kind of particle, exhibiting consistent properties throughout.

Particle Arrangement in Gases

• In the gaseous state, particles are very spread out and move in straight-line, random paths, allowing for high energy and low density.

Homogeneous Mixtures

• A homogeneous mixture has a uniform composition and consists of only one phase, often referred to as a solution.

Components of Mixtures

• The solute is the particle in a mixture that is present in smaller proportions and is dissolved in the solvent.

Test your knowledge on chemical changes that alter the composition of substances and lead to the formation of new substances. Explore how energy is transferred and transformed during changes of matter, involving the system and surroundings.