freestyle topics Flashcards
How has a salt been formed in this reaction?
A hydrogen ion (of an acid) has been replaced by a metal
ion
State what is meant by the term empirical formula.
The simplest whole number ratio of atoms (of each
element) present in a compound
Describe what is meant by the term ionic lattice, in terms of the type and arrangement of particles present.
Repeating pattern
of oppositely charged ions
What is meant by the term covalent bond ?
A shared pair of electrons.
Explain what is meant by the term electronegativity.
The ability of an atom to attract electrons
(Electron pair) in a (covalent) bond
Explain why a CH2Cl2 molecule is polar.
The dipoles do not cancel out
OR
Because the molecule is non-symmetrical
Calcium hydroxide is both a base and an alkali. Refer to any relevant ions in your answer.Explain what is meant by the terms base and alkali.
Base: A substance which readily accepts H+ ions (from an
acid)
Alkali: releases OH– ions into (aqueous) solution
A student prepares a solution of calcium nitrate from calcium carbonate.
What reagent would the student need to use?
Write the equation for the reaction.
Nitric acid OR HNO3
CaCO3 + 2HNO3 Ca(NO3)2 + H2O + CO2
What is meant by the term isotopes?
Atom(s) of an element
AND
with different numbers of neutrons (and with different
masses)
Different isotopes of antimony have the same chemical properties.Explain why
same number of electrons in outer shell
OR
same electron configuration OR electron structure
Define the term relative atomic mass.
The (weighted) mean mass of an atom (of an element)
OR
The (weighted) average mass of an atom (of an element)
compared with 1/12th (the mass)
of (one atom of) carbon-12
Predict the shape of a molecule of SbCl3.
(Trigonal) Pyramidal
(Sb has) three bonding pairs AND one lone pair of
electrons
Pairs of electrons repel
SbCl3 molecules are polar.Explain why.
There is a difference in electronegativities (between Sb and Cl) OR (Sb-Cl) bonds are polar OR have a dipole OR Dipoles seen on the diagram The molecule is not symmetrical AND dipoles do not cancel
A salt used as a fertiliser has the empirical formula H4N2O3.
Suggest the formulae of the ions present in this salt.
NH4
+ NO3
–
Suggest the formula of the acid used to prepare Ca3(PO4)2.
H3PO4
me a base which could be used to prepare Ca3(PO4)2.
Calcium oxide OR calcium hydroxide OR calcium
carbonate
State and explain two anomalous properties of ice caused by hydrogen bonding.
Property 1
Ice is less dense than water
Explanation 1
The molecules in ice are held apart by hydrogen bonds
OR
ice has an open lattice OR structure
Property 2
Ice has a relatively high melting point
Explanation 2
Hydrogen bonds are relatively strong
OR
Hydrogen bonds are stronger (than other intermolecular
attractions or forces)
OR
More energy is needed to overcome hydrogen bonding
Define the term relative isotopic mass.
Mass of the isotope compared to 1/12th
OR
mass of the atom compared to 1/12th
(the mass of an atom of) 12C
State the formulae of the two main ions present in the solution of Al2(SO4)3.
Al3+
SO4
2–
What does ‘•x H2O’ represent in the formula Al2(SO4)3•x H2O?
(The number of) water(s) of crystallisation
Why is Na3PO4 described as a salt of H3PO4?
The hydrogen ions OR H+ OR protons (of phosphoric
acid) are replaced by sodium ions OR Na+
Suggest why PH3 has a lower boiling point than NH3.
the intermolecular forces are weaker in PH3
What is a dative covalent bond?
Both electrons have been donated by one atom
) Define the term relative atomic mass.
The (weighted) mean mass of an atom (of an element)
OR
The (weighted) average mass of an atom (of an element)
compared with 1/12th (the mass)
of (one atom of) carbon-12