Final answer:
To identify an unknown metal, a student can conduct various laboratory investigations, including determining the metal's melting point, conducting a flame test to observe characteristic colors, and measuring the metal's density. These methods are useful in identifying metals as they possess unique physical properties.
Step-by-step explanation:
The student is performing laboratory investigations to identify an unknown metal. Determining a metal's melting point is a method used to identify it, as different metals have distinct melting points. For example, Exercise 72 mentioned that Substance A with a melting point of 1135 °C is likely metallic, which gives us a clue about its identity. A flame test can also provide valuable clues based on the color the metal imparts to the flame, which can be a hallmark of certain metal ions. Measuring the density of the metal is another method that can help determine the identity of the metal since density is a property specific to each metal and can be compared to known densities of metals. In the context of Exercise 3.5.1B, it should be noted that melting point and density are physical properties, whereas flammability is a chemical property.
The investigations for identifying the metal include determining its melting point, conducting a flame test, and measuring its density. Therefore, the correct answer to the student's question is d) All of the above are correct. Additional exercises such as Example 9.4, which involves calculating the specific heat of a metal, can also be used to assist in the identification process, as different metals have different specific heats.