Vocab - cScience Flashcards
(37 cards)
What shape are bucky balls?
Spherical.
Give one use of bucky balls.
Delivering drugs.
Molecular formula of propanone.
C₃H₆O
Why does propanone have a low boiling point?
Weak intermolecular forces.
Explain why graphite is:
- A good electrical conductor.
- Soft and slippery.
Each carbon atom is covalently bonded to three others, leaving each atom with a free electron. This forms a sea of delocalised electrons, which are free to move and carry charge.
Graphite is soft and slippery because there aren’t any strong covalent bonds between the layers - the layers are instead held together by weak intermolecular forces, meaning they can easily slide over eachother.
Isotope definition.
An isotope is a different form of an element with the same number of protons but a different number of neutrons.
Calculate the Mr of gallium.
69.8
Number of electrons and number of neutrons in gallium isotope.
31, 38
What is the most likely formula of a gallium ion?
3+
Give two reasons why the discovery of gallium helped Mendeleev’s periodic table to become accepted.
1) He predicted gallium’s properties before it was discovered.
2) He left a gap for it in the periodic table.
Relative atomic mass of R.
96
Atom economy equation.
(Mass of useful / mass of total reactants) x 100.
Calculate the percentage atom economy for extracting tin in this reaction.
73%
Evaluate possible methods for extracting tungsten from tungsten oxide.
You can’t use carbon to extract tungsten, because rather than displacing it from tungsten oxide, it reacts with tungsten to form tungsten carbide.
Hydrogen and iron both extract tungsten from it’s compound, but iron is cheaper than hydrogen, therefore iron should probably be used, as it produces tungsten solid and is cheap.
Give two observations you could make when a small piece of potassium is added to water.
1) The metal floats and melts.
2) The metal lights on fire.
Complete and balance the equation for the reaction of potassium with water.
2K + 2H₂O -> 2KOH + H₂
Explain why the reactivity of elements changes going down group 1.
As you go down group 1, there are more electron shells. This means the electron on the outermost shell gets further and further away from the nucleus, which means there are weaker electrostatic forces of attraction between the nucleus and electron as you go down the group. This means that the electron is lost more easily, which shows it’s more reactive.
Dot and cross diagram to show what happens when atoms of sodium and oxygen react to produce sodium oxide.
Na - one shell, one electron Na - one shell, one electron \+ O - one shell, six electrons -> [Na - one shell, zero electrons] + \+ [O - one shell, 6 crosses, 2 dots]
Why is oxygen described as being reduced in the reaction between sodium and oxygen?
Because it gains one electron from each sodium atom (two in total).
Explain why sodium oxide has a high melting point.
There’s strong electrostatic forces of attraction between the oppositely charged ions, which require a lot of thermal energy to overcome.
Give one reason for:
- Step 2
- Step 5
- Step 6
2 - to speed up the reaction
5 - to ensure all of the substances have fully reacted
6 - to remove insoluble substances from the mixture
How should filtrate be evaporated gently in step 7?
Heat the filtrate in an evaporating dish until crystals start forming.
Calculate the volume of chlorine needed to react with 14g of iron.
9dm3
Which substance could be a metal?
C
