Flashcards in C2 Deck (27)
Who made the first proper Periodic Table?
What did creator of the first Periodic Table do?
He left gaps for undiscovered elements.
How many outer shell electrons are in oxygen?
In which group and period of the table would you find the element with electronic structure 126.96.36.199?
Group 2 and Period 4.
Why does Ionic bonding occur?
For the elements to obtain a full outer shell.
What ions do Ionic bonds include?
Ions with opposite charges.
Give examples of the properties ionic bonds have.
-high melting and boiling points
-molten phase can move and conduct electricity
-dissolve easily in water
How do Covalent bonds obtain a full outermost shell?
By sharing electrons.
What are the properties of covalent bonds?
-atoms within molecules are held together by strong electrostatic force
-forces of attraction between molecules are weak
--> low melting and boiling points
-don't conduct electricity
Give two similarities and differences between Diamond and Graphite, in terms of their structure and properties.
Similarities: Made by Carbon Atoms, high melting points
Differences: Graphite can conduct electricity and graphene slide past each other,, delocalized electrons can move.
State the size of nanoparticles.
Explain the benefits of nanoparticles having a high surface area to volume ratio.
A larger proportion of their atoms can react with the substances they come into contact with.
Give three examples of the use of nanoparticles.
Any 3 of the following: Sunscreen, deodorants, nanomedicine, lubricant coatings, surgical masks, wound dressings.
What are polymers?
Lots of small molecules called monomers joined together.
Describe the properties of metals.
-high melting/ boiling point, good conductors of electricity
Copper is a metallic element. State what property of copper makes it suitable for using in electrical circuits, and explain why it has this property.
Copper has a sea of delocalised electrons which move freely through the metal, carrying the electric charge.
Is the boiling point of metallic structures high or low?
Ally buys a carton of juice labelled ‘100% pure apple juice’. Decide whether the use of the word ‘pure’ matches the scientific definition.
No. As apple juice consists of water, sugar and other substances, it is a mixture of different substances and is therefore impure.
Steel is produced by adding carbon to iron to make it stronger. Would you expect steel to have a higher or lower melting point than pure iron?
Lower. Impure substances create a lower melting/ boiling point in comparison to pure substances.
What type of distillation could you use to separate a mixture of liquids?
Substance A, B and C have boiling points of 97, 65 and 78 degrees. Suggest a method to separate the mixture and put the order of collection from first to last.
B - C - A.
A student is given a solution made by copper sulfate crystals in water. Describe a method that they could use to extract pure copper sulfate crystals from the solution.
Crystallisation. Pour the solution into an evaporating dish and gently heat the solution. The solvent will evaporate and the solution will become more concentrated. Once crystals start to form leave the dish to cool, filter and leave them in a warm place to dry.
How is Thin Layer Chromatography different from Paper Chromatography?
The stationary phase of Paper Chromatography is paper instead of a thin layer of solid.
How can you calculate the Rf value for each chemical?
Rf = distance travelled by solute/ distance travelled by solvent
How can you interpret gas chromatograms and identify gases?
By observing the retention time- amount of time it takes a chemical to travel through the tube.
What is relative atomic mass?
The relative atomic mass of an element is the average mass of one atom of the element, compared to 1/12 of the mass of one atom of carbon-12