18 carat gold is a mixture.
Classify the following as element, mixture or compound:
18-carat gold
The mass percent of gold in a sample of 24 carat gold is 100. What is its mass percent a sample of 18 carat gold?
18-carat gold contains 18 parts of gold and 6 parts of copper by mass. Calculate the concentration of gold and copper in 18-carat gold in %(m/m).