General Chemistry Online: Companion Notes: Matter: Classifying matter

2. Antoine Lavoisier, the "father of chemistry", listed lime as a chemical element in his table of 33 known elements. Which of the following observations shows that lime cannot be an element?

	When a certain soft metal is burned in oxygen, lime is produced (with no other products).
	Lime melts at a temperature of 2572°C.
	Lime reacts with water, generating a large amount of heat.
	Lime and carbon dioxide are produced when limestone is roasted.

3. The meteorite ALH84001 contains tiny bubbles of gas trapped in the rock. The chemical composition of the gas in these bubbles matches the composition of the Martian atmosphere as determined by Viking spacecraft in the 1970's. The meteorite is an example of a(n)

binary compound

homogeneous mixture

solution

element

heterogeneous mixture

4. A blue crystalline material is heated strongly in a test tube. A clear liquid condenses around the mouth of the tube and the crystals gradually lose their blue color and become white powder. Every gram of blue crystal produces 0.36 g of clear liquid and 0.64 g of colorless powder. The same weight relationships are observed for samples of the crystals taken from many different sources. These observations are consistent with the hypothesis that the blue crystals are:

a heterogeous mixture

a compound

a solution

a wet salt

an element

5. A solid melts gradually between 85°C and 95°C to give a milky, oily liquid. When a laser beam shines through the liquid, the path of the beam is clearly visible. The milky liquid is likely to be:

a heterogenous mixture

a solution

an element

a compound

General Chemistry Online! Classifying matter