Calculate the number of gold atoms present in 0.450 g of a gold ring made from 22 carat gold. Given that the atomic mass of gold is 197 and pure gold is 24 carats.

Calculate the number of gold atoms present in 0.450 g of a gold ring m

1.	Calculate the number of gold atoms present in 0.450 g of a gold ring made from 22 carat gold. Given that the atomic mass of gold is 197 and pure gold is 24 carats.
Answer» Solution :22 carat gold means 22 parts by weight of pure gold are PRESENT in 24 parts of the sample. Pure gold present in 0.450 g of gold ring. `=22/24 xx 0.450 = 0.412 g` Gram atomic MASS of gold = 197.0 g This mass contains `6.022 xx 10^(23)` ATOMS `therefore` Number of gold present in `0.412` g of pure gold `=(6.022 xx 10^(23))/(197.0)xx 0.412 =1.26 xx 10^(21)` Hence, the given gold ring contains `1.26 xx 10^(21)`atoms of gold.