Paper 3-2020 Flashcards
(18 cards)
How oxides of nitrogen are formed in engines
N2+2O2__>2NO2 .High temps provides enough energy to break N2 bonds
Heterogeneous catalyst
Catalyst has different phase from reactants. Speeds up reaction without being used up
Why are C particulates formed in both diesel and petrol vehicles
Incomplete combustion
Why does NaO form a Sol with higher ph than MgO
Oxide ions react with H2O to form OH ions. NaOH is more soluble than MgOH
Contact process
V2O5 +SO2–>V2O4+ SO3
2V2O4+ O2–>2V2O5
Why complexes from, transition metals are coloured
Absorbs some wavelengths of visibible light to excite electrons in d orbital. Remaining wavelengths that weren’t absorbed transmitted to give substance colour
Describe how calibration curve is produced to find conc of complex
- Measure absorbance for range of known concentrations
- Plot absorbance v conc.
- Read value for conc for measure absorbance from graph
Graphical method to process measure results to confirm reaction is 1st order
- Plot conc. against time and take tangents to find gradient
- Plot rate against conc
- Straight line through origin is 1st order
How to decrease % uncertainty
Use bigger masses
Substance and conditions in std H2 electrode
H2 and 100 kpa
1moldm-3 and H+/HCL/HNO3
Pt electrode and temp 298K
Prep solution of acidified TiO2+
Weigh 8g ofTiSO4
Dissolve in 0.5moldm-3 H2SO4
Transfer to volumetric flask and make up to mark
Std enthalpy of formation of silver iodide
AgI(s)—>Ag+(s)+1/2I2(s)
Bond enthalpy
R-p
Why is HNO3 added before AgNo3
Prevent ppt of silver compounds other than halides forming
What won’t act as a ligand
CH4
What compound decolourises acidified KMnO32-
FeSO4
What is formed when carboxylate salt is hydrolysed under acidic conditions
CAsalt+HCl—>CA+NaCl
Titration showed vol of acid added from burrete was larger than expected why?
Burette only rinsed with water
