Chapter 7 science Flashcards
(25 cards)
Matter
Anything that has mass and takes up space. (Physical objects, earth, air, fire, water, etc…) (sound and light are not matter)
Atoms
Small particle – building block of matter
At the center of the atom is a nucleus. A nucleus is made of protons with a + charge and Neutrons with a neutral charge.
Electrons ( - charge) move quickly around the nucleus in an electron cloud.
The properties of an atom are based on the number of protons in its nucleus. This determines the properties of the matter.
Substances
Matter with a composition that is always the same (same combination of atoms)
made of compounds and elements
Elements
A substance that consists of just one type of atom (aluminum, hydrogen, oxygen)
118 known elements and 118 types of atoms
Each type of atom contains a different number of protons in its nucleus. (aluminum has 13)
Compounds
A type of substance containing atoms of two or more different elements.
Carbon dioxide is a compound. its atoms are made of carbon and oxygen.
chemically bonded together (CO2 , H2O
chemical formulas
a combination of symbols and numbers used to represent a compound.
Mixtures:
Matter that can vary in composition
A Heterogeneous Mixture is a mixture in which individual substances are not evenly mixed (like a salad)
is a mixture in which individual substances are not evenly mixed (like a salad)
Homogeneous Mixture (a solution) is mixture in which the substances are evenly mixed would be (like orange juice)
is mixture in which the substances are evenly mixed would be (like orange juice)
Solvent:
Solute:
The majority of the mixture (water usually)
The other substances in a solution (sugar, orange pulp, etc…)
Compounds vs Solutions:
A compound is a single substance or just the solvent
Solutions are two or more substances mixed together.
A physical property:
is a characteristic of matter that you can observe or measure without changing the identity of the matter.
The arrangement of atoms determines whether matter is a substance or a mixture
The arrangement of atoms determines the properties of different types of matter.
When substances mix together and form mixtures, the properties of the substances that made up the mixture are still present.
States of matter examples
Aluminum is an element, and a solid at room temperature.
water is a compound, and a liquid at room temperature.
air is a mixture, and a gas at room temperature
What determines the state of matter?
It depends of how close together the particles are and how fast they are moving
Atoms that make up matter are constantly moving and are attracted to each other.
Mass
Mass is the amount of matter in an object.
Size dependent
Mass is not the same as weight, mass is the amount of matter while weight is the pull of gravity
Mass does not change with location like weight
Volume
Volume is the amount of space something takes up.
size dependent
Melting point:
the temp at which substances change from solid liquid
Boiling point
: the temp at which substances change from liquid to gas
boiling point for water is 100 deg celsius at sea level
Density
Density is mass per unit volume of a substance
a bowling ball is denser than a foam ball
Electrical conductivity
is the ability of matter to conduct, or carry along, an electric current.
(copper)
Thermal conductivity
is the ability of matter to conduct thermal energy.
(metal)
Solubility
the ability of 1 substance to dissolve into another.
(kool aid powder is soluble) sand is not
Separating mixtures
When substances form a mixture, the properties of the substances stay the same.
