ch 2: nature of matter. what is matter? matter is anything that has mass and volume substance is...
TRANSCRIPT
What is Matter?
matter is anything that has mass and volume
Substance is pure matter made of only one type of particle
Volume
rectangular solid with regular sides, Use the formula Volume = l x w x h
Label your answer with Cubic centimeters or cm3 or CCs
• solids with irregular sides: use displacement method:
• Fill a graduated cylinder with water, add the material and measure how much water is pushed out of the way
• Label your answer using cubic centimeters or milliliters
volume
Gas: measure the size of the container
Label your answer using cubic meters or cubic centimeters
• Mass is the amount of matter in an object
• Mass is measured with a balance using grams as the base metric unit
mass
MATTER HAS DENSITY
• Density is: the amount of matter in a given space.
• Density is calculated: Density = Mass
Volume
density
Density is measured with a balance (for mass) and a graduated cylinder (for volume)
Label your answer with the metric units g/ml or g/cm3
• Water’s density is 1g/ml or 1 g/ cm3
• Every pure substance has its own density, density is a characteristic property used to identify a substance
density
MATTER CAN BE DESCRIBED BY ITS PROPERTIES.
• A property is a characteristic used to describe an object.
•Both chemical and physical properties are used to identify and describe matter
1. Physical property - a characteristic of a pure substance that can be observed without changing it into another substance
2 types of properties
Examples of physical properties:
• color• taste• odor• volume • mass• density
viscosity solubility melting point boiling point Electrical conductivity thermal conductivity
•Chemical property - a characteristic of a pure substance that describes its ability to change into a different substance with new properties
Chemical property
Examples of chemical properties:
Ability to rust Ability to tarnish Flammable Reacts with baking soda Reacts with acids Reacts with bases
Matter can be identified by its properties that do not change even when the sample size changes.
Some of these properties are: density, melting point, boiling point, and what it reacts with.
Elements:
Elements are pure substances made up of only one type of atom. They cannot be broken down into a simpler substance
There are about 115 known elements, 92 natural Rest are man-made
element
Each element has its own atomic structure and a unique set of physical and chemical properties that identify it
the smallest particle of each element is the atom
Compounds
a pure substance composed of two or more elements
chemically combined in a set ratio smallest piece of a compound
is called a molecule.
compounds
Most elements in nature are combined with other elements
most substances we use everyday are made of compounds.
compounds
When elements are chemically combined they form compounds with properties that are DIFFERENT from the original elements
Examples of property changes
Water – clear liquid formed from two highly explosive gasses
Table salt – white crystalline solid necessary for cellular function formed from an explosive silvery metal and a poisonous green gas
compounds
Chemical formula - Compounds combine according to certain ratios, there is a set “recipe” Ex: water is ALWAYS 2 hydrogen
atoms bonded to 1 oxygen atom
Mixtures
A mixture is 2 or more substances PHYSICALLY combined
Each substance keeps its original physical properties
mixtures
Parts of a mixture can be separated by PHYSICAL changes
Substances in the mixture can be any amount in the mixture (no set “recipe”)
Heterogeneous mixtures have particles big enough to see, they are not evenly mixed and some particles are big enough to separate out.
2 kinds of mixtures
2 kinds of mixtures
Homogeneous mixtures look the same throughout, they are evenly mixed and do not separate on their own.
Solutions a homogenous mixture with the smallest
particle size Concentrated – a lot of one substance
dissolved in another. Ex. Very salty salt water
Dilute – not very much of one substance dissolved in another
Ex. Not very much salt in salt water
Matter can change in two ways
Physical change: a change in form or appearance, but no new substance is created; most physical changes are easy to undo.
Examples of physical change Change of State: solid to a liquid;
liquid to a gas, etc. Change in form or shape dissolving salt in water bending metal crushing breaking
Chemical change
a change that occurs when one or more substances are changed into entirely different substances with new properties
Examples of chemical changes
Souring milk, bubbling or Fizzing when 2 things
combine, Iron rusting, Bleach taking color out of
something Burning
Conservation laws Law of Conservation of Matter -
Matter is not created or destroyed in any chemical or physical change
Law of conservation of energy- Energy is neither created nor destroyed, but can change forms
Energy
Energy – ability to do work or cause change. Like matter, energy is never created or destroyed in chemical reactions, it can only be transformed (changed from one form to another)
energy
Thermal energy – total energy of all of the particles in an object
Temperature – measure of the average energy of random motion of particles of matter
energy
Endothermic change – a change in which energy is taken in. Ex: melting ice
Exothermic change – a change in which energy is released. Ex: combustion – heat and light are produced.