Chemistry Test #1 Flashcards
What are the TWO characteristics of matter?
It has mass and occupies space
What is the smallest complete unit of matter?
Atom
Difference between pure substances and mixtures?
a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together.
Difference between an element and a compound?
Element: Pure substance consisting of one type of atom. Compound: Pure substance consisting of two or more different atoms.
Difference between homogenous and heterogenous mixtures?
Heterogeneous mixtures have visually distinguishable components, while homogeneous mixtures appear uniform throughout
What is another name for a homogeneous mixture?
Solution
Examples of chemical properties?
flammability, toxicity, acidity, reactivity (many types), and heat of combustion.
Examples of physical properties?
density, color, hardness, melting and boiling points, and electrical conductivity.
Difference between chemical and physical changes?
Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula.
A substance boils and evaporates.
Chemical or physical change.
Physical Change.
The substance is still made up of the same chemical composition just at a different temperature.
Wood is chopped up and cannot be turned back into a log.
Chemical or physical change?
Physical change.
The wood is still the same wood, just chopped up.
Salt dissolves in water
Chemical Change.
The salt dissolves in water, becoming a solution and is irreversible.
5 signs a chemical change has happened?
color change, formation of a precipitate, formation of a gas, odor change, temperature change
What are subatomic particles?
Compare them on size, location, and electric charge.
Protons, Neutrons, Electrons.
PROTONS- 1AMU
NUETRONS- 1AMU
ELECTRONS -0 AMU
Protons and neutrons are in the centre of the atom, making up the nucleus. Electrons surround the nucleus
Protons have a positive charge. Electrons have a negative charge. Neutrons have no charge.
What is the Atomic number?
the number of protons in the nucleus of an atom
What is the Atomic mass?
Mass of an atom