Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (i) Compounds always contain at least two different elements.

Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (g) The number 0.0033 has more significant figures than 0.033.

In 2009, a team from Northwestern University and Western Washington University reported the preparation of a new 'spongy' material composed of nickel, molybdenum, and sulfur that excels at removing mercury from water. The density of this new material is 0.20 g/cm³, and its surface area is 1242 m² per gram of material. (b) Calculate the surface area for a 10.0-mg sample of this material.

Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (d) Elements can exist in any of the three states of matter.

You are assigned the task of separating a desired granular material with a density of 3.62 g/cm³ from an undesired granular material that has a density of 2.04 g/cm³. You want to do this by shaking the mixture in a liquid in which the heavier material will fall to the bottom and the lighter material will float. A solid will float on any liquid that is more dense. Using an Internet-based source or a handbook of chemistry, find the densities of the following substances: carbon tetrachloride, hexane, benzene, and diiodomethane. Which of these liquids will serve your purpose, assuming no chemical interaction takes place between the liquid and the solids?

Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version. (f) A hypothesis is more weakly supported by experimental evidence than a theory.