(a) (i) Zinc blende is mainly Zinc sulphide and in industry it is converted to ZnO by flames to burn off the sulphur as SO2 which is then used to make sulphuric acid.
(ii) Reduction of ZnO to Zn:-
2ZnO + C = CO2 + 2Zn
(b) This is called sacrificial anodic protection. The zinc ( which is more reactive than iron) when in contact with the oxygen in the air is oxidised and in the process loses its electrons. These travel through the electrolyte to the iron. The electrons then reduce any iron oxide to iron: fe2+ + 2e ---> Fe.
Answer:
The compound you will use is the Dibasic phosphate
Explanation:
Simple phosphate buffer is used ubiquitously in biological experiments, as it can be adapted to a variety of pH levels, including isotonic. This wide range is due to phosphoric acid having 3 dissociation constants, (known in chemistry as a triprotic acid) allowing for formulation of buffers near each of the pH levels of 2.15, 6.86, or 12.32. Phosphate buffer is highly water soluble and has a high buffering capacity,
In this case the most efficient way is to disolve the dibasic compound which in the reaction with the water will form the monobasic phosphate.
To make the buffer you have to prepare the amount of distillate water needed, disolve the dibasic phospate, and then adjust with HCl or NaOH depending on the pH needed.
The units for molarity is moles of solute per liter of solution which means if you multiply the molarity of a solution by its volume you get how many moles of solute are in the solution. (0.75Mx0.5L=0.375mol NaCl)
Then you can multiply the moles of sodium chloride (0.375 mol) by its molar mass (58.45 g/mol) to get 21.92g of sodium chloride. That means there is 21.92 grams of sodium chloride in 500mL of 0.75M solution. I hope this helps. Let me know if anything is unclear.
This movement is known as convection or convection currents. This occurs due to the fact that warmer fluid is of lower density than colder fluid. This causes warmer fluid to rise and colder fluid to sink. This creates circulatory currents within the body of the fluid.
B
Protect themselves from predators
