1) Answer is: 5.
Chemical dissociation of aluminium sulfide in water:
Al₂S₃(aq) → 2Al³⁺(aq) + 3S²⁻(aq).
There are five ions, two aluminium cations and three sulfide anions.
2) Answer is: 4.
Chemical dissociation of aluminium fluoride in water:
AlF₃(aq) → Al³⁺(aq) + 3F⁻(aq).
There are four ions, one aluminium cation and three fluoride anions.
Aluminium has oxidation +3, because it lost three electrons, to gain electron configuration as noble gas neon.
No. of mol. of NaOH used: (30/1000)*0.5= 0.015mol
Mole ratio of NaOH:H2SO4= 2:1
No. of mol. of H2SO4: 0.015/2= 0.0075mol
Conc. of acid= 0.0075/(50/1000)= 0.15moldm^-3
Hope it helps, drop a thanks
Creates one million jobs (500 000 direct and 500 000 indirect).
Accounts for about 18% of GDP (8.6% direct, 10% indirect and induced).
Is a critical earner of foreign exchange at more than 50%.Accounts for 20% of investment (12% direct).
Attracts significant foreign savings (R1.9-trillion or 43% of value of JSE).
Accounts for 13.2% of corporate tax receipts (R17-billion in 2010) and R6-billion in royalties.
Accounts for R441-billion in expenditures, R407-billion spent locally.
Accounts for R78-billion spent in wages and salaries.Accounts for 50% of volume of Transnet’s rail and ports.
Accounts for 94% of electricity generation via coal power plants.
Takes 15% of electricity demand.
About 37% of the country’s liquid fuels via coal.<span>
</span>With South Africa’s economy built on gold and diamond mining, the sector is an important foreign exchange earner, with gold accounting for more than one-third of exports. In 2009, the country’s diamond industry was the fourth largest in the world. South Africa is also a major producer of coal, manganese and chrome.
__________________________________________________________
