U7 - building blocks of matter

Question 1

Def: Element

Answer 1

Pure substance that consists of one kind of atom, and cannot be broken down further by chemical means

Question 2

Def: Mixture

Answer 2

Impure substance that consists of two or more kinds of substances that are physically combined

Question 3

Def: Alloy

Answer 3

moulten mixture of metals and other elements

Question 4

Def: Compounds

Answer 4

: Pure substance consisting of two or more elements that are chemically bonded.

Question 5

The formula of a compound tells you

Answer 5

• Which elements the substance contains
• The proportion of each element in the compound

Question 6

What is the reaction of iron with sulfur

Answer 6

Two elements are mixed, and then heated, a chemical reaction occurs.
The red glow that spreads through the mixture is an indication that the reaction is exothermic.
New compound is formed that is different from the elements, iron and
sulfur, that were mixed together.

Question 7

Def: Crystal lattice

Answer 7

orderly arrangement of particles (atoms, ions, molecules) in a solid

Question 8

Properties of crystal lattice

Answer 8

• The lattice can be molecular or giant.
• Giant lattice can be covalent, ionic or metallic
• In a giant lattice the pattern is repeated endlessly

Question 9

Explain the arrangement of alloys

Answer 9

• In alloys the regular arrangement of atoms is disrupted, because different
  metals have different sizes
• This will cause alloys to be harder and less malleable than pure metals,
  alloying reduces slip between layers of atoms

Question 10

Properties of alloys

Answer 10

• Stronger
• Harder
• More resistant to corrosion
• Poorer conductor than the pure metal