transition metals Flashcards
How can a colorimeter be used to determine the concentration of a solution of transition metal complex?
- use an appropriate filter in the colorimeter
- measure the absorbance of a range of concentration of known solutions or standard solutions (?)
- plot a calibration curve of absorbance(y) -concentration(x)
- measure the absorbance of unknown concentration and compare to calibration curve
Explain why the coordination number of a complex does not change when H2O and NH3 ligands are exchanged
Both ligands are similair size
What is the reacting ratio of Fe 2+ ions with MnO4- ions in a redox titration?
5:1
What is the linear complex that silver forms with ammonia ligands called.
Tollen’s reagent
Why is the autocatalysed reaction between C2O4- and MnO4- initially slow?
- activation energy is very high
- as the two negative ions repel each other
What is the definition of a ligand
- A molecule or ion that forms a coordinate bond with a transition metal
- by donating a **lone **pair of electrons
How can hetrogenous transition metal catalyst be poisioned
- impurities block the active site
- reduce its efficiency
What is the complex formed when
[Cu(H₂O)₆]2⁺ undergoes partial ligand substitution with ammonia?
- [Cu(NH3)4(H2O)2]2+
- only 4 out of 6 ligands are substituted with ammonia
What type of isomerism can sqaure planar complexes display?
cis-trans isomerism
What are three examples of heterogenous transition metal catalysts?
- Iron in haber process
- V2O5 in contact process
- Nickel in the hydrogenation of ethene
What are the four oxidation states and colours of stable ions of Vanadium?
- (VO2)+ [+5] = yellow
- (VO)2+ [+4] = blue
- (V)3+ = green
- (V)2+ = violet
What is a heterogenous catalyst?
- The catalyst in a different phase to the reactants.
What is the name of the effect where bidentate and multidentate ligands replace monodentate ligands from complexes?
- the chelate effect
what is a metal complex
