C1 Chemistry Top 35 Flashcards
What is the difference between an element, compound and mixture?
Element - Made up of one type of atom that are chemically bonded.
Compound - Two or more different atoms that are chemically bonded.
Mixture - Two or more different atoms that aren’t chemically bonded.
Give the formula for a) carbon dioxide b) carbon monoxide c) methane
a) CO^2 b)CO c)CH^4
Balance the following equations:
a) Na + Cl 2 => NaCl
b) Na + H 2 O => NaOH + H 2
c) Al + FeO => Al 2 O 3 + Fe
a) 2Na + Cl 2 => 2 NaCl
b) 2Na + 2H 2 O => 2NaOH + H 2
c) 2Al +3 FeO => Al 2 O 3 + 3Fe
Which method of separation is useful to separate an insoluble solid from a liquid?
Filtration
Which method of separation is useful to separate a soluble solid from a liquid?
Evaporation or crystallisation
Describe the process of distillation.
The action of purifying a liquid by a process of heating and cooling.
Which method of distillation would you use to separate liquids with similar boiling points?
Fractional distillation
In chromatography the baseline needs to be drawn in pencil, why?
So it wont run / dissolve in the solvent / split up
Name the 3 subatomic particles in an atom and state their mass & charge.
Proton + Mass = 1 Neutron No charge Mass = 1 Electron 1/2000th
Why is an atom neutral?
Equal number protons and electrons
How many protons, neutrons and electrons are there in sodium (Na)?
11 Protons 11 Electrons 12 Neutrons
What is an isotope and give an example with relation to abundancies.
Isotopes are different forms of the same element, which have the same number of protons, they may have different
numbers of neutrons.
They have the same atomic number, but different mass number. Eg C12 and C13
Explain how Rutherford’s Scatter experiment disproved the Plum Pudding Model.
He projected a beam of alpha particles at a thin sheet of gold. He expected all of the particles to pass through. Most
particles did pass through, however a small number were deflected backwards. This led to the discovery or the
positively charged nucleus.
Who discovered the existence of neutrons?
Chadwick
Why did Newland call his periodic table the Law of Octaves?
He noticed similar elements every 8 th place
He called this the law of octaves as it was similar to musical scales
Why didn’t people believe Newlands Law of Octaves?
Unfortunately the pattern only worked for the first 17 elements. Elements were placed in the same groups with
completely different properties!
How did Mendeleev arrange the elements and why did people believe him instead?
Mendeleev lined up the elements in order of increasing atomic mass (similarly to Newland)
He started new lines to put similar elements in the same columns
He even left gaps when the pattern didn’t fit
What is the key difference between Mendeleev’s periodic table and the modern periodic table?
- Between 1894 and 1898 a whole new family was discovered by British scientists Lord Rayleigh and Sir William
Ramsay; The Noble Gases
These were not predicted by Mendeleev as they are very unreactive and therefore don’t have many noticeable
properties! - In 1913 the electronic structure of the atom was discovered. Several different scientists working together realised
that if the elements were put in order of increasing atomic number instead of mass, it all fits nicely!
Describe what is meant by a
a) Period
b) Group
a) Period number of shells
b) Group number electrons outer shells
Why are Lithium, Sodium and Potassium in the same group?
1 electron in outer shell
State the common names for:
a) Group 1
b) Group 7
c) Group 0
a) Group 1 Alkali Metals
b) Group 7 Halogens
c) Group 0 Noble gases
State 3 properties of the alkali metals.
low density
low melting and boiling points
very reactive
Complete the following word equations showing the different reactions of the alkali metals:
a) Lithium + Water
b) Potassium + Chlorine
c) Sodium + Oxygen
a) Lithium + Water Lithium hydroxide and Hydrogen
b) Potassium + Chlorine Potassium chloride
c) Sodium + Oxygen Sodium oxide
Universal indicator can be add to the water to determine whether the reaction between lithium and water was
successful. Why?
Changes to purple with alkali
As you go down group 1, what happens to the:
a) Reactivity
b) Melting/Boiling Point
a) Reactivity increases
b) Melting/Boiling Point decreases
As you go down group 7, what happens to the:
a) Reactivity
b) Melting/Boiling Point
a) Reactivity decreases
b) Melting/Boiling Point increases
Group 7 are naturally coloured vapours, with the exception of Bromine. State the colour and state of the following:
a) Fluorine
b) Chlorine
c) Bromine
d) Iodine
a) Fluorine Yellow
b) Chlorine green
c) Bromine brown
d) Iodine purple
What is a displacement reaction?
If a reactive element comes into contact with the compound of a less reactive element achemical
reactionmay take place. The less reactive element isremovedfrom the compound andreplacedby the more reactive element.
Complete and balance the following symbol equation:
Br 2 + NaI
Br 2 + 2 NaI 2 NaBr + I 2
Give 1 property of the noble gases and link this to their electronic structure.
Non-reactive due to full outer shell
Explain why the boiling points of the noble gases increase as you move down the group.
Strong intermolecular forces
Krypton is a gas at -153◦C, predict what state Argon is in at this temperature.
Gas
State 3 properties/uses which are specific to the transition metals.
Hard and strong
Good conductors of heat and electricity
They have high melting points.
They are not very reactive.
They have a high density.
They are useful as catalysts.
Their ions are often 2+ but may be variable.
Malleable
Ductile
Make coloured compounds
Compare the difference between Group 1 and the transition metals for the following properties:
a) Hardness
b) Reactivity
c) Melting Point
a) Hardness group 1 soft
b) Reactivity group 1 more reactive
c) Melting Point group 1 lower melting point
Where can you find the following on the periodic table and what type of ion does each make:
a) Metals
b) Non-metals
a) Metals left side make + ions
b) Non-metals right side - ions
