Chemistry

Problem

1. (a) On analysis a sample of uranium ore was found to contain 0.277 g of

{}_{82}\text{Pb}^{206}

and 1.667 g of

{}_{92}\text{U}^{238}

. The half-life period of

\text{U}^{238}

4.51 \times 10^9

year. If all the lead was assumed to have come from decay of

{}_{92}\text{U}^{238}

, what is the age of earth? 2. (b) An ore of

{}_{92}\text{U}^{238}

is found to contain

{}_{92}\text{U}^{238}

and

{}_{82}\text{Pb}^{206}

in the mass ratio of 1:0.1. The half life period of

{}_{92}\text{U}^{238}

4.5 \times 10^9

year. Calculate the age of ore.