Passage I
A mineral hydrate (MH) is an ionic compound that has associated H2O molecules. Dehydration (removal of all H2O) of an MH produces its anhydrous salt (an ionic compound that has no associated H2O molecules), which may differ in color from the MH. Table 1 shows, for each of 4 MHs, the chemical formula of one formula unit of the MH, its color, and the color of its anhydrous salt.
Figure 1 shows the mass of a sample that was converted from chalcanthite to CuSO4 as its temperature was increased from 0°C to 350°C.
Table 2 shows the solubility in H2O of each anhydrous salt at 20°C, 40°C, 60°C, and 80°C.
5. Based on Figure 1, the change that occurred in the sample as it was heated from 175°C to 300°C would be best represented by which of the following chemical equations?
Your Answer is
Correct Answer is A
Explanation
Look at figure 1, the substance corresponding to 175 degrees is CuSO4·H2O, which is the reactant of this reaction; while the substance corresponding to 300 degrees is CuSO4, which is the product of this reaction, and the other product is H2O