5. Structure and Properties of Materials Flashcards
1
Q
How are element, compounds and mixture different?
A
- Element only have one element
- Compounds have 2 or more element chemically combined
- Mixture has two or more elements or compounds that are not chemically combined
2
Q
Properties of Ionic structure
A
- High melting and boiling point due to strong electrostatic forces of attraction
- Ionic compounds are hard but brittle
- Ionic compounds are often soluble in water but insoluble in organic solvent
- Ionic compounds conduct electricity when molten or in aqueous solution
3
Q
Properties of molecular
substances
A
- Low melting/boiling point due to the weak intermolecular forces of attraction. (However, as the molecule gets larger, mp/bp gets higher)
- Simple covalent bonds are insoluble in water than soluble in organic solvent
- Simple covalent substances do not conduct electricity
4
Q
Define alloys
A
An alloy is a mixture of metal with one or more other elements
5
Q
Properties of metals and alloys
A
- Pure metals are malleable and ductile
- Metals and alloys usually have high melting and boiling points
- They are good conductors of electricity
6
Q
Why does a metal have high density?
A
- closely packed in an orderly arranged manner
7
Q
why are metals malleable?
A
- As they are arranged in orderly manner in regular layers
- When there is force applied, layers of atoms can easily slide over each other
8
Q
why does metals have high melting/boiling point?
A
- As the electrostatic forces of attraction between the positive ions and sea of delocalised of electron is strong
9
Q
Why are metals conductor of heat and electricity?
A
- sea of delocalise metals allow the free and mobile electrons to carry electrical charges
10
Q
What are the advantages of using alloy?
A
- increased hardness and strength
- decreased melting/boiling point
- Improve appearance
