Answer:
25%
Explanation:
Half life means that 50% of the sample is gone at 3.3 years. This means that an additional 3.3 years (total 6.6 years) will reduce the sample a further 50% from the point at 3.3 years. In numbers, this means 50% of 50% (0.50*0.50), which is 25%.
Answer:
5.79 × 10^23 Oxygen atoms
Explanation:
Number of Oxygen atom in the compound = 4×3 = 12
Molar mass of Al2(SO4)3 = 342 g/mol.
No of mole = mass/molar mass = 2.74/342 = 8.01×10^-03 mole
2.74g of Al2(SO4)3 × 1 mole of Al2 (SO4)3 / 342g of Al2 (SO4)3 * 12 mole of Oxygen/ 1mole of Al(SO4)3 * 6.02×10^23 Oxygen atom/ 1 mole of Oxygen
= 5.79×10^23 Oxygen atoms
