Lab2

Geology 111 Lab 2 Worksheet Matter & Minerals 1. Watch the video on “Observations & Inferences”. Respond to the following. a. In your own words. Define “Observations” and “Inferences”. Inferences are the logical conclusions we make from our observations, which are what we immediately see, smell, hear, taste or touch. b. What are the two types of observations? Qualitative & Quantitative c. Identify the following observations as either Qualitative or Quantitative (the first one is done for you). Observation Qualitative Quantitative The flower has seven petals x The cheetah runs faster than the dog x John is three inches taller than Mark x On a scale from one to ten, Skittles are a 5 for sourness x The apple is very sweet x 2. Watch the video on “Ionic & Covalent bonds”. Respond to the following. a. Salt is made of two elements: Na and Ci . These two elements are held together by a(n) Ionic bond. b. Water is made of two elements: hydrogen and oxygen . These two elements are held together by a(n) covalent bond. 3. Now watch the video “Properties of Ionic and Covalent Compounds”. Respond to the items below: a. What is the chemical formula for Salt? NaCl b. What is the chemical formula for Sugar? C 6 H 12 O 6 c. Did solid sugar conduct electricity? No d. Did sugar dissolved in water conduct electricity? No e. Did solid salt conduct electricity? No f. Did salt dissolved in water conduct electricity? Yes g. What is the difference between how salt and sugar are dissolved (at the molecular level?) Salt forces between sodium and chlorine within the molecule are being broken and the sodium ion and chorine ion are being freed and they conduct electricity from one led to the next. h. Which of the two substances has a higher melting temperature? Salt i. What might happen if you try to melt a solid substance in a Pyrex pot? The Pyrex would shatter, and it will be hot glass blowing in every direction. j. If salt (an ionic compound) and sugar (a covalent compound) are 1

Geology 111 Lab 2 Worksheet Matter & Minerals typical for each type of compound, write a statement about the conductivity and melting temperatures of ionic and covalent compounds. Since ionic compounds like salt are freely moving ions that have a capacity to carry an electric charge, they typically have high conductivity when dissolved in water. However, because to the high electrostatic interactions between oppositely charged ions in their crystal lattice structures, they often have high melting temperatures when they are solid. Because covalent compounds do not separate into ions in solution, like sugar, they typically have poor conductivity in both the solid and dissolved states. Since they are bound together by weaker covalent bonds rather than powerful ionic interactions, their melting temperatures are often lower than those of ionic compounds. 4. Go to the Minerals Properties and Identification website and match up the minerals from Moh’s hardness scale to the sample numbers. Place the sample numbers in the table below by using the process of elimination. Note that not all the minerals are present, when that happens, write “Not Present” in the Sample # column. Mineral Hardness Sample # Talc 1 20 Gypsum 2 1 Calcite 3 17 Fluorite 4 14 Apatite 5 8 Orthoclase 6 9 Quartz 7 4 Topaz 8 Not Present Corundum 9 5 Diamond 10 Not Present  Color: Salt is usually white or colorless in its pure form.  Taste: Salt has a salty taste.  Phase: Salt is typically found in the solid phase at room temperature and standard pressure, it can melt into a liquid state when heated to its melting point.  Shape: Salt frequently takes the shape of tiny cubic or octahedral crystals. Depending on the circumstances during crystallization, the particular form of salt crystals can change. 2