Science - year 8 exam - matter Flashcards
Compare pure substances and mixtures and give an example of each
Pure substances consist of only ___ element
Mixed substances consist of ___ or more elements
Compare pure substances and mixtures and give an example of each
Pure substances consist of only one element
Mixed substances consist of two or more elements
Explain the difference between a heterogenous and homogenous mixture and give an example of each
Heterogenous mixtures are full of different _______ making it easy to ___ what is inside.
Homogenous mixtures have only ___ element, meaning that humans cant see what is inside without a _________.
Explain the difference between a heterogenous and homogenous mixture and give an example of each
Heterogenous mixtures are full of different elements making it easy to see what is inside.
Homogenous mixtures have only one element, meaning that humans cant see what is inside without a microscope.
Define the following terms:
Atom
An atom is the s______ unit of ordinary matter that forms a chemical e_______.
Element
An element is a pure s________ consisting only of atoms that all have the same numbers of protons in their atomic n_____.
Compound
A chemical compound is a chemical substance composed of many i_______ molecules composed of atoms from more than one e_______ held together by chemical bonds.
Molecule
A molecule is an e_________ neutral group of two or more atoms held together by chemical b____.
Define the following terms:
Atom
- An atom is the smallest unit of ordinary matter
- that forms a chemical element.
Element
An element is a pure substance
- consisting only of atoms that all have the same numbers of protons
- in their atomic nuclei.
Compound
- A chemical compound is a chemical substance
- composed of many identical molecules
- composed of atoms from more than one element
- held together by chemical bonds.
Molecule
- nA molecule is an electrically neutral group
- of two or more atoms
- held together by chemical bonds.
Recall the names of the three subatomic particles that make up atoms:
P______, N_______, E________.
Recall the names of the three subatomic particles that make up atoms:
Protons, neutrons, electrons.
Where is the majority of the mass of an atom located?
The mass of the atom is concentrated in the N______.
Where is the majority of the mass of an atom located?
The mass of the atom is concentrated in the nucleus.
Compare the terms atom and element
An element is the simplest form of a s________.
An atom is the part of an e______.
Compare the terms atom and element
An element is the simplest form of a substance.
An atom is the part of an element.
Who was the scientist who put together the periodic table as we know it today?
Russian chemist Dm____ Me_____eev
Who was the scientist who put together the periodic table as we know it today?
Russian chemist Dmitri Mendeleev
Why did he leave some blanks in the periodic table?
Mendeleev left gaps in his table to place e_______ not known at the t___.
Why did he leave some blanks in the periodic table?
Mendeleev left gaps in his table to place elements not known at the time.
Describe the trend in atomic number across a period of the periodic table from left to right:
The atomic r____ of atoms generally d_______ from left to right across a period.
Describe the trend in atomic number across a period of the periodic table from left to right:
The atomic radius of atoms generally decreases from left to right across a period.
List the characteristics of metals:
C________
Melting and _____ ______
S____
D______
List the characteristics of metals:
Conduction
Melting and boiling points
State
Ductility
Decide whether each element is a metal or a non-metal:
Oxygen?
Sodium?
Iron?
Neon?
Potassium?
Helium?
Zinc?
Decide whether each element is a metal or a non-metal:
Oxygen? - Non-metal
Sodium? - Metal
Iron? - Metal
Neon? - Non-metal
Potassium? - Metal
Helium? - Non-metal
Zinc? - Metal
Compare physical and chemical changes and give an example of each:
Chemical changes involve the f_______ of new chemical elements or c________.
e.g.
Physical c_______ do not lead to new chemical s________ forming.
e.g.
Compare physical and chemical changes and give an example of each:
Chemical changes involve the formation of new chemical elements or compounds.
e.g.
Physical changes do not lead to new chemical substances forming.
e.g.
List the five signs of a chemical change:
C_____ change
Formation of a pre______
Formation of g__
O___ change
Tem_______ change.
List the five signs of a chemical change:
Colour change
Formation of a precipitate
Formation of gas
Odor change
Temperature change.
Classify the following changes as either physical or chemical:
Cutting your hair
- Physical or chemical?
Baking a cake
- Physical or chemical?
Scrunching up a piece of paper
- Physical or chemical?
Bending a piece of metal
- Physical or chemical?
Dissolving salt in water
- Physical or chemical?
Adding magnesium to hydrochloric acid to make magnesium chloride and hydrogen
- Physical or chemical?
Mixing two clear liquids together and forming a yellow liquid
- Physical or chemical?
Classify the following changes as either physical or chemical:
Cutting your hair
Physical
Baking a cake
chemical
Scrunching up a piece of paper
Physical
Bending a piece of metal
Physical
Dissolving salt in water
Physical
Adding magnesium to hydrochloric acid to make magnesium chloride and hydrogen
chemical
Mixing two clear liquids together and forming a yellow liquid
chemical
Describe what happens between the bonds between atoms during a chemical change:
In a chemical reaction, bonds between a____ in the reactants are broken and the atoms re______ and form new bonds to make the p_______.
Describe what happens between the bonds between atoms during a chemical change:
In a chemical reaction, bonds between atoms in the reactants are broken and the atoms rearrange and form new bonds to make the products.
