Chemistry 2 Flashcards
Which one is the Mass number and what does it tell you?
The top one and the total number of protons and neutrons.
Which one is the Atomic Number and what does it tell you?
The bottom one and how many protons are in that atom.
How do you find out the number of Neutrons in an atom?
Take the atomic number away from the mass number.
What is a compound?
Two or more different atoms are chemically bonded together.
What is an Isotope?
Different atomic forms of the same element which have the same number of protons but a different number of neutrons. (They have different mass numbers.)
Is Ionic bonding about transferring or sharing electrons?
Transferring electrons.
What does Ionic bonding form?
Ions which are charged particles (strongly attracted to each other due to their opposite charges.)
What structure do Ionic compounds have?
A regular lattice structure, closely packed together with very strong bonds.
What properties do Ionic compounds have?
High melting and boiling points due to the strong attraction between the ions, when melted they carry electric current and easily dissolve in water and carry electric current when they are.
What are atoms that have lost or gained electrons and what structure do they have?
Ions and have an electronic structure of a noble gas.
What happens in Covalent bonding?
Atoms share electrons with each other.
When drawing Ionic bonding diagrams, what does it consist of?
ggggggggggggggggggggggggggggggggggggg
When drawing Covalent bonding diagrams, what does it consist of?
ggggggggggggggggggggggggggggggggggggggggggggg
What is a double Covalent bond?
Where 2 pairs of electrons are shared between the atoms
O = O
Why do Simple molecular substances have low melting and boiling points?
The forces of attraction between the molecules are weak. The molecules are easily parted from each other. The intermolecular forces get broken when put to a high temperature.
Why don’t Simple Molecular substances conduct electricity?
There are no ions inside them so there is no electrical charge.
What are Giant Covalent Structures called?
Macromolecules.
How are the atoms in Macromolecules bonded and what does it lead to?
The atoms are bonded by strong Covalent bonds which means they have high melting and boiling points.
What Covalent structure does Diamond have?
Made up of carbon atoms with each one forming 4 bonds. It has a very large, rigid structure. This makes diamond the hardest natural substance.
What Covalent structure does Silicon dioxide have?
It is what sand is made of and each grain of sand is one giant structure of silicon and oxygen.
What Covalent structure does Graphite have?
Each carbon atom forms 3 Covalent bonds. This creates layers which are free to slide over each other. Graphite is soft and slippery and as the layers are held so loosely together they can be rubbed off onto paper (pencil!)
What is special about Graphite?
It is the only non-metal to conduct electricity and heat. This is because each carbon atom has one delocalised (free) electron which are free to move so conduct heat and electricity.
What is the proper name for free electrons?
Delocalised.
Why are Metals good conductors of heat and electricity?
The delocalised electrons are free to move so heat and electricity can pass through easily.
Why are Alloys stronger than Pure Metals?
When 2 metals are mixed together they have different sized atoms which distort the layers so they can’t slide over each other. This makes them harder.
What is Nitinol and how does it work?
It’s a ‘smart’ metal alloy made up of nickel and titanium. When it’s cool you can bend it but bend it too far and it stays. But if you heat it, it returns to its original shape.
What are the main uses of Nitinol?
Glasses frames and Braces as the mouth is warm so it tries to return to its remembered shape and pulls the teeth with it.
What does a Nanoparticle contain?
Fullerenes which are molecules of carbon shaped like hollow balls or closed tubes. All the covalent bonds make the nanotubes very strong.
What are the 8 new uses of nanoparticles?
1 - Industrial catalysts as they have a large surface area to volume ratio 2 - Sensors 3 - Stronger and lighter building materials 4 - Sun lotion 5 - Deodorant 6 - Nanomedicine 7 - Lubricant coatings 8 - Electric circuits.
What are the properties of Thermosoftening polymers?
Individual tangled chains which are free to slide over each other. Weak intermolecular forces. Low melting points so you can remould it many times.
What are the properties of Thermosetting polymers?
Strong intermolecular forces between the polymers chains called crosslinks which hold them together. They don’t soften when heated and are strong, hard and rigid.
What affects the properties of a polymer?
The starting materials and reaction conditions.
How do you make Low Density polythene?
Made by heating ethene to 200C under high pressure. It’s flexible and used for bags and bottles.
How do you make High Density polythene?
Made at a lower temperature and pressure with a catalyst. It’s more rigid and used for water tanks and drain pipes.
How do you work out the Relative Atomic mass of an element?
Mass/Atomic number
How do you work out the Relative Formula mass of an element?
Add up all the Relative atomic masses.
What is a Mole?
The Relative Formula mass of a substance in grams.
How can Artificial colours be seperated?
Chromotography.
How does Chromotography work?
Extract the colour from a food sample into a cup and add a solvent. Put spots of the solution onto pencil baseline filter paper. Roll up the sheet and put it in a beaker with a solvent but keep the baseline above the solvent.
What should you see if one dye is a mixture of colours?
Different colour dyes which form spots in different places.
