Lecture 3 1.3 Predicates and Quantifiers 1.4 Nested Quantifiers.
Sections 1.3 and 1.4 Science 7 Mr. Nigh
-
Upload
carmel-richards -
Category
Documents
-
view
219 -
download
3
description
Transcript of Sections 1.3 and 1.4 Science 7 Mr. Nigh
Matter Combines to form different substances
Most of the substances in the world are mixed
Matter can be pure or it can be two or more substances mixed together
Drinking water may appear to be pure, but may have many minerals dissolved in it.
Often the difference between pure and mixed may only be visible on the atomic or molecular level
ElementsAn element is a substance that
contains only a single type of atom
The number of atoms is not important
An element cannot be separated into other substances
CompoundsCompounds are substances that
consist of two or more different types of atoms bonded together
Some types are made of molecules such as water and carbon dioxide
Others are made of elements bonded together like salt
Salt is a compound that has very different properties then the elements that make it up
Sodium and Chlorine are poisonous by themselves
But when combined, they create a compound (table salt) that is safe to eat
MixturesA mixture is a combination of
different substances that remain the same individual substances and can be separated by physical means
For example: a fruit salad is not a different kind of fruit, the parts can be separated by physical means
Parts of mixtures can be the same or different throughout
SoilSeveral handfuls of soil may have
different properties in different parts of your backyard
The soil in the yard is thus an example of a heterogeneous mixture, different properties in different parts of the mixture
Kool-aidYou know the color and flavoring in
Kool-aid are there because you can see and taste them
One drop of the liquid is essentially the same as another drop
Thus this is an example of a homogeneous mixture
Comparing mixtures and compounds
Substances in mixtures remain the same, in compounds new substances are formed by atoms that bond together
Mixtures can be separated by physical means, compounds only by breaking bonds
Proportions in mixtures vary, compounds are fixed because the type and number of atoms are always the same
States of MatterThe four familiar states of matter
are solid, liquid, gas and plasmaWhen a substance changes from
one state to another, the molecules in the substance do not change
However the arrangement of molecules does change giving each state of matter its own characteristics
SolidIt has a fixed volume and a
fixed shapeParticles are close together
and form a regular patternParticles cannot move from
one location to another, fixed
LiquidLiquid has a fixed volume, but
no fixed shapeUsually the shape of the
container it is inParticles are attracted and
close, but are not fixed and may move from one place to another
GasA gas has no fixed volume or
shapeParticles are not close together
and may move from one place to another
Space between particles can increase or decrease with pressure
Gas Behavior• Gas molecules are always in
motion, continually hitting each other and applying pressure to the sides of any container they are in
• As in a bicycle tire, the more molecules are put in, the harder the outside of the tire becomes
• The speed at which gas molecules move depends on the temperature, higher temperature molecules move faster
PlasmaPlasma
Although it is the least familiar state of matter to us here on Earth, plasma is actually the most common form of matter – 99% of all visible matter in the Universe.
In a plasma, a significant number of electrons have such high energy levels that no nucleus can hold them.
Volume, temperature, and the pressure of gasses have a
unique relationship--Difficult Concept-- Listen
IncreaseDecrease
Stay the same
If the temperature of the gas stays the same, increasing the pressure of the gas decreases its volume
If the volume stays the same, increasing the temperature increases the pressure
If the pressure of the gas stays the same, increasing the temperature of the gas also increases the volume
Which two characteristics determine the state of matter?
The arrangement and the motion of particles
Which state of matter has particles that can slide past each other but cannot move
freely in any direction
liquid
What happens to the volume of a gas if the temperature stays the same and the pressure on the
gas increases?
Itdecreases
What happens to the pressure of a gas if the volume stays the
same and the temperature increases?
Itincreases
What happens to the volume of a gas if the pressure stays the same and the temperature
increases?
It increases