general Chemistry Flashcards
gcse study
What type of compound is electrolysis used on, and what is it used to do
ionic compound, it is used to separate the compound into the elements it is made of
What has to happen to the ions for electrolysis to happen, how does this happen
the ions have to be free to move around, this can happen through melting the compound or dissolving it in water
what are electrolytes
ionic compounds that dissolve in water to make a solution that conducts electricity
what is the difference between intramolecular forces and intermolecular forces
intramolecular forces are the forces between the atoms that makes up a molecule
intermolecular forces are the forces present between molecules
what are the properties of an ionic compound
ionic compounds can form giant lattices structures,
they have high melting and boiling point because the ions have a strong electrostatic attraction meaning a lot of energy is needed to separate the oppositely charged ions
cannot conduct electricity when solid because the ions are not free to move around, in order for the compound to conduct electricity it must be in a liquid state, this can be done by turning it in to a solution(dissolved in water) or melting it
what are the properties of transition metals
lower reactivity compared to alkali metals
higher density compared to alkali metals
stronger and harder compared to alkali metals
higher melting point than alkali metals
often used as catalyst
can form different colour compounds
can form ions with different positive charges
why is sodium more reactive that lithium
because it is a group 1 metal or alkali metal and these metals have one electron on the outside shell meaning in order for the element to be stable it has to lose that one electron, and sodium is below lithium on the periodic table meaning the outside electron shell is further away making the electron less strongly attracted to the positively charged nucleus, this is because it is greater distance from the positively charged nucleus
what happens when an alkali metal reacts with:
.water
.chlorine
.oxygen
with water the metal floats on the surface and melts creating a metal hydroxide, when reacting with water enough energy is released to melt the metal
with chlorine a metal chloride is formed, which dissolves in water to give a colourless solution
with oxygen the metal rapidly turns from silvery shiny to dull this is because a metal oxide is formed
why are covalent bonds strong
Covalent bonds are strong because the shared electrons are attracted to the nucleus of both atoms
what force is used in metallic bonds and why
electrostatic force it is between the positively charged metal ions and the negatively charged delocalised electrons
small molecules are often what states at room temperature? why is this
small molecules are often gas or liquid this is because they have low boiling and melting points
what tend to be the properties of substances with small molecules
substances with small molecules tend to have lower melting points and boiling points, and do not conduct electricity
why do big molecules have higher boiling and melting points than smaller molecules
big molecules attract other molecules with stronger intermolecular forces, this means they have a high melting and boiling point, big molecules also don’t contain delocalised electrons meaning they can’t conduct electricity
what are polymers
Polymers are large, chain like molecules that can extend for thousands of atoms
The intermolecular forces between polymer molecules are strong compared to the intermolecular forces between small molecules. This means that polymers melt at higher temperatures than substances with small molecules. They are solids at room temperature
what are some of the properties of giant covalent structures
no specific formula they can be any size
very high melting point
covalent structures exist as 1 large molecule or structure there is no intermolecular forces in them because it is just one molecule
what are some properties of pure metals
they have a high melting and boiling point because of the strong electrostatic forces between the positive metal ions and the negative delocalised electrons
they are also soft and malleable because the ions are the same size and are arranged in layers, they easily move over each other when a force is applied
what are alloys
An alloy is a combination of 2+ elements, where at least 1 is a metal
the atoms of different elements are different sizes this makes them stronger than pure metals because it makes it harder for the layers to slide across each other
what is graphite
Graphite is an allotrope (form) of carbon every atom is bonded to 3 other carbon atoms with a strong covalent bond
graphite is formed in layers of carbon with weak intermolecular forces this makes it soft
graphite conducts electricity because carbon is only bonded to 3 other carbon atoms meaning one electron is free to be delocalised
what is Graphene
graphene is just one layer of graphite meaning it has weaker intermolecular bonds than graphite, it is lighter than graphite, more flexible than graphite and can conduct electricity because it has delocalised electrons
what are fullerenes, and what can they be used for
a form of carbon having a large spheroidal molecule consisting of a hollow cage made up of sixty or more atoms
Catalysts
Lubricants
As vehicles for transporting drugs into our bodies
what are Carbon nanotubes
Carbon nanotubes are fullerenes that take the shape of a cylinder.
They have a tiny diameter but can be incredibly long. they are also exceptionally strong for their size because of the covalent bonds and they can conduct electricity because of their delocalised electrons
what are the uses of nano particles
deodorant
Catalysts
Transparent cosmetics
Computer chips
Delivery of medicines to specific areas of the body
what is a exothermic reaction and what is a endothermic reaction
An exothermic reaction is when energy is lost from the reacting chemical in the form of heat
An endothermic reaction is when energy enters the chemical this usually results in loss of temperature
what happens to the position of equilibrium if you increase the temperature of a reversible reaction
if you increase the temperature the position of equilibrium will change and because of Le Chatelier’s law the reaction will try to return to normal because of this the position of equilibrium will move towards the endothermic reaction which increases the amount of products made by the endothermic reaction