Inorganic Chemistry Answers

What weight of limestone should be taken so that 1/20 the the number of milligrams of CaSO⁴, obtained will represent the percentage of CaO in the mineral?

3. Draw or sketch a schematic diagram for ash analysis on our limestone sample.

1. A mixture of BaO and CaO weighing 2.212 g is transformed into mixed sulfates (BaSO4 and CaSO4) weighing 5.023 g.

a. Calculate the number of grams of CaO and of BaO in the original mixture.

b. What weight of limestone should be taken so that 1/20 the number of milligrams of CaSO4 obtained will represent the percentage of CaO in the mineral?

explain how the sulfuric acid is formed

Lead metal is obtained from lead sulfide through the following reaction:

2PbS(s) + 2C(s) + 3O₂(g) → 2Pb(s) +2CO(g) + 2SO₂(g

For question (b) above, calculate the mass of lead metal obtained.

1. A gram of soil sample as received contains 15.00% water. After oven drying to remove the mixture, it was found to contain 16.00% K. Find the %K in the original sample as received. 

1. A groundwater at pH 7.5 is in equilibrium with P_C02 = 10^-1•5 atm and with siderite (FeC0₃(s)). Determine the total dissolved Fe concentration.

1. In some water softening operations, Mg²⁺ must be removed from solution along with Ca²⁺. What pH is required to lower TOT Mg to 10 mg/L as CaC0₃ by precipitation of Mg(OH)₂(s)?

3. Nuclear chemistry

1. Calculate the binding energy per nucleon in MeV for the iron isotope with an atomic number of 26 and a mass number of 56, 56Fe26 which has an atomic mass of 55.9349 amu.

2. Calculate:

a. The rate constant for the radioactive disintegration of cobalt-60, an isotope used in cancer therapy. 60Co27 decays with a half-life of 5.2 years to produce 60Ni28.

b. The fraction and the percentage of a sample of the 60Co27 isotope that will remain

after 15 years.

c. How long it takes for a sample of 60Co27 to disintegrate to the extent that only 2 % of the original amount remains?

d. The half-life of 216Po84 is 0.16 s. How long does it take to reduce a sample of it to the negligible amount of 0.000010 % of the original amount (1.0 x 10-7 times the original amount)?

2. Oxidation-Reduction reactions

1. Iron (II) is oxidised to iron (III) by chlorine. Use the half reaction method to balance the equation for the reaction: Fe2+ + Cl2 → Fe3+ + Cl- 2. The dichromate ion oxidizes iron (II) to iron (III) in acid solution. Balance the equation:

Cr2O 2-

+ H3O+

+ Fe2+

→ Cr3+

+ Fe3+

+ H2O, by the half-reaction method