thermodynamics/ chemical reactions / chemcial bonds Flashcards
What is the triple point on a phase diagram known as?
the point on a phase diagram at which the three states of matter: gas, liquid, and solid coexist.
What bond has a ΔEN ≤ 0.4 value? covalent ionic polar metallic
covalent bond
what bond has a ΔEN > 1.7? polar covalent metallic ionic
IONIC BOND. ΔEN > 1.7 = ionic bond (metals + non-metals) || ΔEN ≤ 0.4 = covalent bond || 0.4 < ΔEN <1.7 =polar covalent || ΔEN<2 = metallic bond
which reaction proceeds spontaneously
exergonic or endergonc?
exergonic proceeds spontaneously. this means it has a negative gibbs free energy as energy is released from system
> ender you need to put work into fighting the dragon so that’s NOT spontaneous
what is meant by the “critical point” on a pahse diagram
Critical point – the point on a phase diagram at which the substance is INDISTINGUISHABLE between liquid and gaseous states
what are the laws of thermodynamics
- energy is conserved - basic :)
2. all spontaneous processes tend towards incresing entropy == DISORDER!
what is name given to reaction that has positive gibbs free energy?
endergonic as you put energy into the system.
> all endergonic are non spontaneous
> ENDER : you need to put work to fight the blaze rods to reach the end so that isn’t a spontaneius thing, so its non spontaneous
what are the oxidation numebrs for oxygen, hydrogen and fluroine
-2
+1
-1
what is the oxidation number for the carbon in methane?
-4
why? +4 for all the hydrogens so 0= +4 +? ?=-4
why would you use half equations?
they show what is happening at each electrode
> oxidation at anode+
> reduction at cathode-
(anions are negatively charged)`
Which of these is not used to completely describe states of matter? A pressure (p) B mass (m) C volume (V) D amount (n) Etemperature (T)
OPTION B
Which of these statements about hydrogen bonds is false?
A Hydrogen bonds are stronger than van der Waals forces
B Hydrogen bonds are weaker than chemical covalent bonds
C Hydrogen bonds are not chemical bonds
D Hydrogen bonds are the only bonds to not directly involve electrons
E Hydrogen bonds can be broken very easily
OPTION D
Hydrogen bonds are very specific overlaps between free electron pairs
What is the most electronegative element, and what is its electronegativity? Oxygen, 3.4 Carbon, 2.5 Sodium, 6.3 Fluorine, 4.0 Nitrogen, 3.0
OPTION D
sodium electronegativity is 0.9
what are the basic features of ionic structures
form lattice MACROstructures
stong intramolecular forces so high melt points
conduct electricity in water or molten
gain or lose electrons to achive stability
what is the VSEPR theory
valence shell electron pair repulsion
electrons are arragnes as afar aprt as possbiel to minimise repulsion!
