Materials Flashcards
difference between metals and non-metals
Metals are malleable and ductile, shiny, good conductors of electricity in the solid state. Usually have high melting points. Forms oxides known as bases when it reacts with oxygen and the reactivity increases down a group. Non-metals are usually dull, brittle, poor conductors of electricity in the solid state, usually have low melting points(not diamond, graphite and silicon), form oxides that are acidic, reactivity decreases down a group. (down a group means in the periodic table)
7 things that show a chemical change
Gas Bubbles Appear. Gas bubbles appear after a chemical reaction has occurred and the mixture becomes saturated with gas. ... Formation of a Precipitate. ... Color Change. ... Temperature Change. ... Production of Light. ... Volume Change. ... Change in Smell or Taste.
Formation of particles in an object with a high melting point.
Any substance that has a HIGH melting point must: have a GIANT structure and have STRONG BONDS.
For non-metals the intermolecular forces are usually very weak. Little energy is needed to break them so the melting point is low.
What are pneumatic systems?
pneumatic: containing or operated by air or gas under pressure.
What are alloys?
Alloys: a metal made by combining two or more metallic elements, especially to give greater strength or resistance to corrosion.
Why are metals more malleable than alloys?
Metals are more malleable than alloys because all the particles are the same size and slide over each other easily but in alloys some particles are different sizes and disrupts the layers.
What is concrete made out of?
Concrete is made by mixing several components, the main ones being aggregate(gravel/crushed rock), sand, and cement(with water)
Concrete hardens over time.
What are SMAs?
SMAs(shape memory alloys) are some alloys that can remember their shape and form. This can be useful in braces. They usually do so when heated to a high temperature and can repair itself back.
What is cement made out of?
- Calcium oxide
- Silica
- Alumina
- Iron
The fire triangle and how does water takes out fires?
In the fire triangle, there is fuel, temperature and oxygen. Water takes out fires because it removes heat, and once one bit of the triangle is removed, the fire is stopped.
Properties of carbon fibre
high stiffness
high tensile strength, low weight to strength ratio, high chemical resistance, high temperature tolerance, low thermal expansion, but high cost.
What is graphene?
Graphene is a single atom thick, the world’s thinnest, strongest and most conductive material. It conducts heat extremely well and can be combined with other materials to make them stronger.
