Matter
Matter is anything that takes up space and has mass
Examples include water, planets, and atoms
Density
Density (D) is the Mass (M) per unit of Volume (V); how packed molecules are Density \(\left(\mathrm{kg} / \mathrm{m}^{\wedge} 3\right)\) is equal to Mass \((\mathrm{kg})\) divided by volume \(\left(\mathrm{m}^{\wedge} 3\right)\)
Law of Conservation of Mass
In an isolated system (enclosed space) mass can be neither formed, nor destroyed through chemical reactions and physical transformations, but will remain constant.
Classification of Matter
Properties of Types of Matter
Atoms: The smallest part of an element that retains its chemical properties.
Elements: A substance where all atoms of the substance share the same properties.
Compounds: A substance which is made up of two or more different elements.
Mixtures: A material that is made up of two or more different substances that are physically mixed together, and can be separated physically. Pure and Impure Substances
A pure substance is a substance that is made up of only one type of molecule. For example:
An Oxygen or Water.
An impure substance is a substance that is made up of two or more different molecules. For
example: Air or Salt Water.
States of Matter
Solid: High density and resistant to changes: For example: Rock
Liquid: Medium density fluid that maintains its volume. For example: Water
Gas: Low density fluid that can change its volume. For Example: Air
Particle Arrangement
STP and Gas Volume
STP stands for Standard Temperature and Pressure, which is the state of an enclosed system when the temperature is \(0^{\circ} \mathrm{C}\), and the pressure is \(1 \mathrm{~atm}\) (the pressure of the atmosphere at sea level).
At STP, one mole, a unit of mass specific to a substance, of a gas takes up 22.4 liters of volume.
Standard Ambient Temperature and Pressure (SATP) is the same as STP with following difference: the temperature is considered \(25^{\circ} \mathrm{C}\), and the molar volume of gas at SATP is 24.8 liters.
Changes of State
When a substance is heated up, its molecules move faster with greater energy. The resulting increase in collisions causes the substance to move farther away from one another, becoming less dense.
Kinetic Theory
Definition: There are 2 parts to kinetic theory
1. the temperature of a substance increases with an increase in either the average kinetic energy of the particles or the average potential energy of separation (as in fusion) of the particles or in both when heat is added
2. the particles of a gas move in straight lines with high average velocity, continually encounter one another and thus change their individual velocities and directions, and cause pressure by their impact against the walls of a container
Relation to Temperature
According to part one, an increase in average kinetic energy or average potential energy as well as an increase in temperature will occur if heat is added. This means that an increase temperature and average energy both occur simultaneously, so they will be proportional to one another.
Particle Movement
Diffusion
Definition
The movement of a fluid from an area of higher concentration to an area of lower concentration.
Factors that Affect Diffusion
Temperature: An increase in temperature increases the rate of diffusion as it increases the energy of the particles, enabling them to move faster.
Concentration Difference: A higher concentration difference will result in a faster rate of diffusion, as a lot more diffusion needs to take place.
Diffusion Distance: The shorter distance the particles have to move, the faster they will be able to diffuse.
Mass of the Molecule: The more mass a molecule has, the rate of diffusion will decrease, as greater mass means that more energy is required to move it.
Terminology and Skills
SI Units: These are the units used for all calculations and investigations in chemistry:
Length – meter ( \(\mathrm{m}\) )
Time – second (s)
Amount of substance – mole (mole)
Electric current – ampere (A)
Temperature – kelvin (K)
Luminous intensity – candela (cd)
Mass – kilogram (kg)
Parallax Error
This happens when you measure with your eyes at a different perspective causing you to get the wrong reading.
Always ensure that the measuring cylinder is placed on a flat surface and crouch down to ensure that you are at eye level with the measurement.
Meniscus
The effect when a liquid forms a small curve at the top in beaker where it’s meant to be measured. Measure from the middle of the curve to get the right reading.