Gold is alloyed with other materials to increase hardness for jewelry.
A) Consider a piece of gold that weight 9.85g and has a volume of 0.675 g/cm3. The jewelry contains gold and silver only with densities of 19.3g/cm3 and 10.5g/cm3. If the total volume is the sum of the gold and silver, calculate the percentage of gold (in mass) in the jewelry.
B) The relative amount of gold in an alloy is expressed in units of karats. Pure gold is 24-karats and percent of gold in an alloy is given as percentage of value. An alloy is 50% and is 12-karats. State the purity of the alloy karats.