Foundations of Chemistry Flashcards
Explain what is meant by the term relative atomic mass of an element.
The weighted mean mass of an atom compared with 1/12 the mass of carbon-12
State two differences between isotopes of the same element.
-Different number of neutrons
-Different physical properties
-Different mass numbers
State similarities between isotopes of the same element.
-Same number of protons and electrons
-Same electronic configuration
What is meant by the term isotopes?
Atoms of an element with different numbers of neutrons and with different masses
Different isotopes of antimony have the same chemical properties.
Explain why.
Same electron configuration
What does OILRIG stand for in terms of electrons
Oxidation Is Loss of electrons
Reduction Is Gain of electrons
What are the different shapes of molecules you can have
-linear
-nonlinear
-triagonal planar
-tetrahedral
-pyramidal
-octahedral
If a molecule has 2 bonded pairs and no lone pairs around the central atom what do you call it
-linear
If a molecule has 3 bonded pairs and no lone pairs around the central atom what do you call it
-triagonal planar
State what is meant by the term ionic bond
The electrostatic attraction between oppositely charged ions
If a molecule has 2 bonded pairs and one lone pair around the central atom what do you call it
-non linear
If a molecule has 4 bonded pairs and no lone pairs around the central atom what do you call it
-tetrahedral
If a molecule has 3 bonded pairs and one lone pair around the central atom what do you call it
-pyramidal
Compare the electrical conductivities of solid and aqueous ionic compound
-solid cannot conduct because it has ions which are in a fixed position whereas it can in an aqueous solution because it has mobile ions
Suggest one modification that the student could make to their method to reduce the
percentage error in the mass of water removed.
- use a balance weighing to 3/more decimal places
-uses a larger mass
The student is not sure that all the water of crystallisation has been removed.
How could the student modify the experiment to be confident that all the water of
crystallisation has been removed?
- heat to constant mass
State what is meant by the term molecular formula.
(Actual) number of atoms of each element
present in a molecule
What is meant by the term alkali
- Releases OH- ions in an aqueous solution
What is meant by the term standard solution
-A solution of known concentration
What is meant by the term acid and weak acid
-(Acid) releases H+ ions/ H+ donor
AND
(weak acid) partially dissociates/ionises in an aqueous solution ✓
What is Meant by the term base
A substance which readily accepts H+ ions
(from an acid)
The student is not confident that their titre is accurate.
Suggest what the student should do next to reduce the effect of any random error in the titration
Repeat titration until (two) titrations are concordant /
agree within 0.1 cm3 (1)
Calculate mean titre from concordant titres (1)
State one disadvantage of using chlorine for the purification of drinking water.
-it is toxic
State, in words, the 3D shape of an s-orbital and a p-orbital.
s- spherical
p-dumbbell
