4.2 Physical Properties Learning Check Answers (Student textbook page 156) 1. Qualitative properties are different kinds of properties, and are not measured. Quantitative properties are measurable differences within one property. 2. DDT is soluble in fat. 3. Even if two substances look alike (qualitative properties), they are likely to have different melting points (a quantitative property). 4. Diamond is harder than glass, so diamond should scratch glass. Section 4.2 Review Answers (Student textbook page 159) 1. Qualitative physical properties are not measured numerically (such as colour, odour, state, texture, lustre, and malleability). Quantitative physical properties can be measured numerically (such as viscosity, melting point, boiling point, solubility, hardness, conductivity, and density). 2. A substance at its melting point changes state, but does not form a new substance. 3. DDT does not break down and, due to its fat solubility, bioaccumulates in fat tissue and biomagnifies so that animals higher in the food chain have higher levels than those lower in the food chain. Seals are higher in the food chain than cod. 4. Conductivity 5. If the density of the material is small, then a large volume can have little mass. 6. 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 = 25.04 𝑔⁄ −3 4.99 𝑐𝑚3 = 5.02 𝑔 ⋅ 𝑐𝑚 ; The sample is iron pyrite. 7. The least dense material (olive oil) is the top layer and the more dense material (vinegar) is the bottom layer. 8. Sample answer: If ice were denser than liquid water, a lake or pond would freeze from the bottom up. Many animals in ponds would die because the lake would become completely frozen.