chem paper 1 Flashcards
what is the structure of an ionic compound?
giant regular lattice structure
what type of force is between what type of ions in ionic compounds?
strong electrostatic forces of attraction between oppositely charged ions
what is the melting/boiling point of iconic compounds like?
high
why are the melting and boiling points of ionic compounds high?
the strong attraction between ions take more energy to break
why can’t ionic compounds not conduct electricity when solid?
the ions are fixed into pace and can’t move
why can ionic compounds conduct electricity when molten?
the ions are free to move, so they can carry an electric current
in what state can ionic compounds conduct electricity?
molten/liquid
what is another way ionic compounds can conduct electricity?
when dissolved in a solution
why can ionic compounds conduct electricity when dissolved?
the ions are free to move in the solution, so they can carry an electric current
what is ionic bonding?
the transfer of electrons between a metal and no metal
what substance is a common example of ionic bonding?
salt
in terms of electrons , what happens to the metal and non metal in ionic bonding?
the metal loses an electron (becomes positively charged), while the non the metal gains an electron (becomes negatively charged)
what is it commonly called when oppositely charged ions are attracted by electrostatic forces?
ionic bonding
what are the 3 types of bonding?
ionic, covalent and metallic
what is the structure of an covalent molecule?
simple molecular substance
what is covalent bonding?
a bond that forms when a pair of electrons are shared between 2 atoms
what diagram is used to show covalent bonding?
dot and cross with overlapping shells
what diagram is used to show ionic bonding?
dot and cross formed like a reactant to product equation
what are the forces between covalent molecules like in contrast to covalent bonding?
very weak
what is the melting/boiling point of simple covalent compounds like?
low
why are the melting and boiling points of covalent compounds low?
because you only need to break the weak intermolecular forces of attraction
what state are covalent compound usually at room temperature?
liquids or gasses
what happens to the intermolecular forces of attraction as a molecule gets bigger?
the force increases
what happens to the melting and boiling points of covalent compounds if the molecule gets bigger?
increase in temp due to more energy needed to break them
do covalent compound conduct electricity?
no
why can’t covalent compounds conduct electricity?
they do not have any free electrons or ions
what are polymers?
chains of covalently bonded carbon atoms
What is the charge of an electron?
Negative
What is the charge of a proton?
Positive
What is the charge of a neutron
Neutral
What is an ion?
An atom or group of atoms with a positive or negative charge
What happens to an atom if it gains or loses and electron?
It becomes an ion
What groups are most likely to form ions?
Groups 1, 2, 6 and 7
What charge do group 1 and 2 elements typically have?
Group 1: 1+
Group 2: 2+
What charge do group 6 and 7 elements typically have?
Group 6: 2-
Group 7: 1-
What are group 1 and 2 elements?
Metals
What are group 6 and 7 elements?
Non metals
What are anions?
Negative ions that have gained electrons
What are cations?
Positive ions that have lost electrons
What stupid saying is a good way to remember the metals reactivity series?
PeopleSayLittleChildrenMakeAZebraIllConstantlySniffingGiraffes.
In which direction does reactivity increase in group 1?
Downwards
In with direction does reactivity increase in group 7?
Upwards
What do the periods down the side of the periodic table represent?
How many shells the element has in its atom
How are giant covalent structures bonded?
Atoms are bonded by strong covalent bonds
What are the melting and boiling points of giant covalent structures like?
High
Why are the melting and boiling points of giant covalent structures high?
The strong covalent bonds require more energy to break them
What are some examples of carbon based giant covalent structures?
Dimond, graphite and graphene
What are diamonds make up of?
A network of carbon atoms that each form 4 covalent bonds
How is graphite different to diamond?
Each carbon atom only forms 3 covalent bonds
What are the forces like between sheets of graphite?
Weak intermolecular forces
What do the week intermolecular forces between sheets of graphite make it good for?
Dry lubrication
What is graphite’s melting point like?
High
What is the equation to find concentration?
Concentration (Gdm³) = mass (g) ÷ volume (dm)
What is the molecular formula?
The actual number of each atom in a molecule
What is the empirical formula?
The simplest ratio of atoms of each element in a molecule
What would the relative formula mass of H₂O₂ when the mass is H = 1 and O = 16?
1 + 1 + 16 + 16 =34
What would the empirical formula of H₂O₂ be?
HO
What does Mr stand for?
relative molecular mass
What does Ar stand for?
Relative atomic mass
What is the formula to find the number of moles?
of moles = mass of element/compound ÷ Mr or Ar of element
What is Avogadro’s constant?
6.02 × 10²³
What does one mole equal?
6.02 + 10²³ (Avogadro’s constant)
What is the mass of one mole of a particular atom equal to?
The atomic mass on the periodic table
What is another way to find the number of moles in a sample?
of moles = mass of sample ÷ mass of one mole of that element
What is another word for “balance” equation?
Stoichiometric
What is it called when the atoms of an element go around in pairs?
Diatomic molecule
What are fullerenes?
Molecules of carbon shaped like closed tubes or hollow spheres
How are atoms usually arranged in fullerenes?
Hexagons (sometimes Pentagons or heptagons)
What is the molecular formula of a buckminsterfullerene?
C60
Are buckminsterfullerene’s stable or unstable?
Stable
What can fullerenes be used for?
‘Caging’ other molecules. This could be used to deliver drugs directly to cells in the body.
What do fullerenes have?
Huge surface area
What is graphene?
A type of fullerene that is a single layer of graphite (one atom thick)
Why can graphite conduct electricity?
Only 3 of the 4 electrons are used in bonds, so the 4th one is delocalised (free)
There are 6 steps to an experiment finding the empirical formula of magnesium oxide what is step 1?
- Weigh the mass of my ribbon an dthe mass of the crucible
There are 6 steps to an experiment finding the empirical formula of magnesium oxide what is step 2?
- Coil mg ribbon and place it in the crucible with the lid at an angle to allow oxygen to enter
There are 6 steps to an experiment finding the empirical formula of magnesium oxide what is step 3?
- Place the crucible into a pipe-clay triangle on a tri pod and light a bunsen burner
There are 6 steps to an experiment finding the empirical formula of magnesium oxide what is step 4?
- After 5 mins/once mg has stopped glowing remove from bunsen burner and allow to cool
There are 6 steps to an experiment finding the empirical formula of magnesium oxide what is step 5?
- Once the crucible is cool to touch, weigh the crucible and its contents
There are 6 steps to an experiment finding the empirical formula of magnesium oxide what is step 6?
- Subtract the mass of the crucible and the Mg from the MgO to find the mass of the oxygen.
From there you can calculate the empirical formula.
What does it mean by a limiting reactant?
Reactions stop when on reactant has been used up. This limits the amount of product formed.
If the amount of limiting reactant is decreased, then the amount of product made will…….
Decrease
If the amount of limiting reactant is increased, then the amount of product made will…….
Increase
If the amount of an excess reactant is increased, then the amount of product made will…….
Not change
What do acids form in water?
H+ ions
What do soluble alkaline bases form in water?
OH- ions
What is produced during a naturalisation reaction?
Salt and water
What produces a naturalisation reaction?
An acid and a base
What is the ionic equation of a naturalisation reaction?
H+ + OH- → H²O
What is the neutralisation equation for hydrochloric acid and sodium hydroxide?
NaOH (base) + HCl (acid) → H2O (water) + NaCl (salt)
What colour would litmus paper change to in acidic solutions?
Red
What colour would litmus paper change to in neutral solutions?
Purple
What colour would litmus paper change to in alkaline solutions?
Blue
What colour would methyl orange change to in acidic solutions?
Red
What colour would methyl orange change to in neutral or alkaline solutions?
Yellow
What colour would phenolphthalein change to in acidic or neutral solutions?
It would remain colour less
What colour would phenolphthalein change to in alkaline solutions?
Pink
All acids ionise in solutions, what does this mean?
Splitting up to produce H+ ions and another ion
What do strong acids do?
Ionise almost completely in water
What are examples of strong acids?
Sulfuric, hydrochloric and nitric acid
What pH do strong acids tent to have?
Low pH (0-2)
What do weak acids do?
Not fully ionise in solutions
What examples of weak acids are there?
Ethanoic, citric and carbonic acid
What pH do weak acids tent to have?
High pH (2-6)
What does acid strength tell you?
What proportion of the acid molecules ionise in water
What does concentration of an acid measure?
How much acid there is in a litre
An acid with a large number of acid molecules compared to the volume of water is said to be…..
Concentrated
An acid with a small number of acid molecules compared to the volume of water is said to be…..
Dilute
What can concentration be measured in?
g dm‐³ or mol dm‐³
What does the concentration of H+ ion increase by?
A factor of 10
If the concentration of H+ ions increases by a factor of 10, what does the pH decrease by?
1
If you decrease the H+ ion concentration by a factor of 10 what happens to the pH?
Increases by 1
What salt would hydrochloric acid produce?
Chloride salt
What salt would sulfuric acid produce?
Sulfate salts
What salt would nitric acid produce?
Nitrate salts
Acid + ______or______ → salt + water
Acid + metal oxide or metal hydroxide → salt + water
Acid + metal carbonate → salt + water + _________
Acid + metal carbonate → salt + water + carbon dioxide
How do you test for hydrogen?
Lit splint test in a test tube. It should a “squeaky pop”
What is the cause of the “squeaky pop” in the test for hydrogen?
The hydrogen burning with oxygen in the air to produce water
How do you test for carbon dioxide?
Bubbling carbon dioxide thought lime water will turn cloudy
Common salts of sodium, potassium and ammonium are…..
Soluble
Nitrates are….
Soluble
Common chloride are…..
Soluble (except silver chloride and lead chloride)
Common sulfates are…..
Soluble (except lead, barium and calcium sulfate)
Common carbonated and hydroxide are……
Insoluble (except sodium, potassium and ammonium ones)
