matter – anything that has mass and volume how do we measure mass in lab? how do we measure...
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Matter
Matter – anything that has mass and volume
How do we measure mass in lab? How do we measure volume in lab? What unit is used to measure mass? What units are used to measure volume?
Pure substance
Atom-smallest building unit of an element that has the same properties of the element.
Pure substance – particles all the same; element or compound
Elements
An element : 1. simplest pure substance 2. composes the Periodic Table 3. The smallest part of an element 4. Elements are written in symbols Fe Cu Ag Au or P K I (always written
in single or double letters; first letter always capitalized
Some common elements and uses
Pass out the periodic table and find these on your own table.
Cl –bleachHg-mercury (barometers)Ne –neon (lights)Ag- silver (jewelry)Au-gold (jewelry)Zr- Zirconium (fake jewelry) He – helium (balloons)
Compound
Compound – different types of elements chemically combined.
Examples: HCl NaCl KI Element symbols are always capitalized
so you can tell the difference between an element and a compound.
Atom
Atom –smallest unit of an element
Each atom of the same element is always identical
Atoms are symbolized by a capital letter or a capital letter and one lower case letter. See Periodic Table.
Molecule
Molecule –simplest unit of a compound; two atoms that are chemically combined
You can have a molecule of a compound or a molecule of an element
See the difference on the board Oxygen, nitrogen, salt, rust
Mixture
Mixture – two or more substance mixed together but not chemically combined
Mixtures do not have formulas because they are not combined in a definite proportion
Two Types of Mixtures
Homogeneous mixture – homo=same; geneous = throughout
A homogeneous mixture is the same throughout
Example : salt water; whipped cream; hand lotion
Solution
Solution is a type of homogeneous mixture formed when one substance dissolves in another
Particles cannot be seen
Example: Kool-aid; stainless steel; candy kiss; atmosphere of gases
Heterogeneous Mixture
Hetero = different geneous= throughout A heterogeneous mixture is different
throughout. Can usually see the particles Example: Trail mix; Lucky charms;
cinnamon and sugar; Chex mix
Types of heterogeneous mixtures
Suspension – particles settle out of solution
Example: pond water
Colloid- particles spread throughout liquid; particles are small and do not settle out quickly
Example: milk and gelatin (jello)
How are compounds classified?
1.pH– acidic, basic or neutral
Review the pH scale. What is an acid? Base? Neutral?
Bases are slippery and taste bitter. When mixing and acid and a base you
always get a salt and water produced.
2. Organic or inorganic- organic compounds contain hydrogen and carbon (come from living or once living things)
(Examples: foods; gasoline, synthetic goods)
Inorganic- come from non living things such as air, minerals, soil.
3. Role in the body – Biochemicals=organic compounds that
make up living things.
4 categories of biochemicals
1. carbohydrates – source of energy 2. Lipids- store excess energy and make
up cell membrane 3. Proteins – one of the most abundant
types of biochemicals; builds cells 4. Nucleic acids- DNA and RNA; genetic
information and used to build protein.
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