<span>The correct answer is 1. compound. There are three elements and not just one so it's not element. Mixtures wouldn't have the same properties that you described but these do so it's a compounds. Solution is not a solid thing but rather a liquid one. The two samples are therefore compounds.</span>
2.2 x 10^-2
0.055 / 250 = 0.00022 - This would be 2.2 x 10^-4, but the question is asking for percent, not proportion, so multiply by 100% to get the percentage.
0.00022 * 100% = 0.022% = 2.2 * 10^-2