physical wrong answers Flashcards
formula for potassium carbonate
K2 CO3
explain why hydrogen bonding causes ice to be less dense than liquid water
there is more space between molecules making it less dense
due to 3D lattice/ring structure in ice
hydrogen bonds are longer than covalent
barium hydroxide soluble or insoluble?
soluble
what is the shape of s-orbital
circle/sphere
what is the shape of a P-orbital
dumbbell/peanut
what is the ionic equation for chlorine molecules becoming chlorate(l) in cold hydroxide ions
Cl2 + 2OH- = 2ClO- + 2H2O + 2e-
aluminium fluoride has a higher sublimation energy than aluminium chloride why?
AlF3 has a larger electronegativity difference
AlCl3 is mostley covalent/small molecule
Aluminium chloride has weaker intermolecular forces/London forces
aluminium fluoride is giant structure/strong electrostatic forces of attraction between ions
-more energy is needed to break
why is a small pinch of calcium carbonate added to acid before staring the reaction
to saturate solution with CO2
explain why ionization energy goes down from magnesium to aluminium and then rises from aluminium to silicon
from Mg to Al electron removed from Al is from P-orbital which is higher and further away from nucleus , forces of attraction are weaker
from Al - Si atomic radius decreases due to additional protons increasing forces of attraction
explain the term polarization applying to magnesium iodide
Polarization is the distortion of anions’ electron clouds due to nearby cations.
how thermochemical data could be used to show there is polarization in magnesium iodide
using electron density map
what is meant by periodicity
repeating patterns across different periods
how does silicon’s structure result in high melting temperatures
covalent bonds throughout the lattice structure therefore lots of energy required to break the bonds
why does magnesium have a higher melting temperature than sodium
more delocalised electrons
higher charge density
requiring more energy to break
why is a potassium ion smaller than a potassium atom
less electrons
electrons in ion are held more tightly
what type of metals have the lowest ionizations in their period
alkali metals
suggest formulae for hydrides of arsenic and selenium
AsH3
SeH2
why is the first ionization of selenium (6) lower than that of arsenic (5)
spin pairing has occurred in selenium P-orbital
electron removed is part of a pair
interelectronic repulsion makes it easier to remove
why would you think water has a lower boiling tempreture than hydrogen sulfide
low boiling point is expected because H2S has more electrons and therefore more london forces
why does water actually have a higher boiling point than H2S
water has hydrogen bonding which is stronger than H2S london forces
why di-methylpropane have a lower boileng tempreture than pentane
branching results in fewer london forces due to less points of contact
how are London forces formed between halogen molecules
uneven distribution of electrons/random movement
resulting in a temporary dipole
which induces second dipole
what are the two bond angles between two water molecules
180
104.5
why is bond angle of water less than ammonia
oxygen has 1 more lone pair
repulsion from oxygen lone pair is greater
lone pair- lone pair repulsion is greater
