Hello everyone!
I was given the following questions for homework, and am pretty confident about my answers to the first three! The fourth however, has me stumped. My course has spoken about metals and alloys, so I know its possible for other metals to be within metals creating a homogenous mixture. In addition, I also know that jewellery is often a less precious metal plated with something like gold, but I can't help thinking that gold is an element and should be a pure substance (even then I don't know what I would write, or how I could classify it as either a solution or heterogeneous mixture)... Thoughts?
42. For each of the following mixtures, explain whether it is a solution or a heterogeneous mixture. For the solutions, identify the solute and the solvent.
a) Cloudy pond water
Cloudy pond water would be considered a heterogeneous mixture. The particles suspended within the water would prevent light from passing through the liquid, and although some particles may be too small to see, larger particles are easily visible.
b) Apple juice
Apple juice can be considered a solution as different particles are not visible, light can pass through the liquid, and solutes and solvents are known. Apple juice from concentrate for example, is a homogenous mixture with the solute being concentrated apple juice – juice that has had all excess water removed for more efficient transportation and packaging – and the solvent being water (added once again before juice is sold).
c) Rainwater
Rainwater can also be considered a solution. It too does not have visible particles, light can pass through it, and as it is a type of water, many solutes are possible. Water itself is a pure substance, but rarely is it found without any substances dissolved within it. In the case of rainwater, a wide variety of different solutes could be present, with a good example being atmospheric gases. Water would be the solvent, and oxides (carbon, sulphur or nitrogen oxides for example) could be possible solutes.
d) 14-karat gold in jewellery
Any help is greatly appreciated!