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Uranium and its Isotopes

Description and Question's below.

Uranium is one the rarer elements in the earths crust, where it occurs mainly as the oxide uraninite (U3O8). In 1938, Otto Hahn and Fritz Strassmann showed the unambiguously that the new, lighter, elements are formed when uranium is bombarded with neutrons, a process which is now called nuclear fission.

Continent Mss of uranium/103 t
Africa 546
Asia 560
Europe 212
North America 447
Oceania 714
South America 164

The table above shows the distribution of uranium deposits around the world, it shows that the deposits are uneven across the world also. T = Tones e.g. 103 kg

(I) China has 6.8% of Asia's uranium resources, what is the calculated mass of uranium in china's resources in kg and scientific notation?
(II) What is the ratio of north Americas uranium resources to the total resources in the world e.g. would be 1 : x
(III) Typically a low-grade uranium ore yields only 0.2% of its mass as uraninite (U3O8), the rest is unwanted soil and rock.

What is the calculated percentage mass of uranium in uranitite

Detailed working out as to how would be helpful to me in this ad other questions on this document to help me understand how and why.

During a lifetime around about 30years a normal nuclear reactor in the civilian sector requires 5x103 tonnes of uranium. What is the calculated mass of the low-grade uranium ore that must be mined to meet the required levels in kg and notation?

(iv) Uranium has 3 naturally occurring isotopes U238, u235 and u234, Natrual uranium is composed of aprox 99.284% U238, 0.711% U235, and 0.0055% U234/

Most fuel sources in reactors around the world is uranium dioxide. UO2 in which the U235 content has been increased to about 3%. This enrichment process is carried out with the compound UF6 which is a gas above 50 C. After enrichment to the desired level, UF6 is reacted with Hydrogen and steam to about 450 C to yield enriched UO2 and hydrogen fluoride which is given off as gas and is show as the following reaction:

UF6 + H2O + H2  UO2 +HF

What is the balanced equation for this using the lowest coefficients and the states of each compound?


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