Physical and Chemical Changes

Matter  Matter – anything that has volume or mass. Atoms are the smallest unit of matter!  Volume – anything that takes up space  Mass – the amount of matter that something is made of

MASS  Mass Measured in grams with a balance

Volume  Liquid Volume measured in liters Meniscus – the curve that you see at the liquid’s surface used to measure the volume 

Volume  Solid Volume Measured in cubic meters (m 3 ) Cubic means “having 3 dimensions”

Remember  Inertia – tendency of all objects to resist any change in motion More Mass Greater Inertia  harder to move an object with a large mass  harder to stop an object with larger mass once moving

A. Matter Flowchart MATTER Can it be separated by physical means? Homogeneous Mixture (solution) Heterogeneous MixtureCompoundElement MIXTUREPURE SUBSTANCE yesno Can it be decomposed by chemical means? noyes Is the composition uniform? noyes

B. Pure Substances  Element matter composed of identical atoms EX: copper

B. Pure Substances  Compound matter composed of 2 or more elements in a fixed ratio properties differ from those of individual elements EX: salt (NaCl)

C. Mixtures Non-specific combination of 2 or more pure substances. Homogeneous Mixture even distribution of components EX: saline solution Two Types of Mixtures Heterogeneous Mixture uneven distribution of components EX: granite

A. Physical Property  A characteristic of matter that can be observed or measured without changing the identity of its matter. can be used to separate mixtures EX: density, color, odor, mass and volume

Chemical Property  A characteristic that indicates whether a substance can undergo a specific chemical change. EX: flammability, reactivity

Physical Change  Physical changes occur when matter changes its property but not its chemical nature.  Physical changes could include a change in: texture, shape, size, color, odor, volume, mass, weight, and density.

Physical Change Remember! properties remain the same reversible can be used to separate mixtures

Physical Change

Chemical Change  Chemical changes are changes matter undergoes when it becomes new or different matter.  To identify a chemical change look for signs such as color change, bubbling and fizzing, light production, smoke, and presence of heat.

C. Chemical Change Remember! properties change irreversible Signs: color change, formation of a gas/solid, release of light/heat

Chemical Change  A chemical change occurs when fireworks are used. Fireworks are made of metals such as magnesium and copper. These change chemically as they light up the sky.

Density  Density describes how much mass is in a given volume of a material.

Density  Solids, liquids and gases are matter, so they all have density.

Determining Density  To find the density of a material, you need to know the mass and volume of a solid sample of the material. 1. Mass is measured with a balance or scale. 2. Use the displacement method or calculate the volume.

Density Problems

What is my Density? Mass g 2.300g 3.25g Volume 50ml 15ml 5cm3 Complete the following questions on a separate sheet of paper as a part of your homework assignment.