Final answer:
The specific heat capacity of an unknown substance absorbing 7.2 joules of energy and with a 7.9 grams mass increasing from 67°C to 98°C is 0.0292 J/g°C. To identify the substance, compare this value to known values in a reference table.
Step-by-step explanation:
To determine the specific heat capacity of an unknown substance, you can use the formula:
Specific heat capacity (c) = q / (m × ΔT)
Where q is the energy in joules, m is the mass in grams, and ΔT is the change in temperature in degrees Celsius.
In this case, the energy (q) absorbed is 7.2 joules, the mass (m) of the substance is 7.9 grams, and the temperature increase (ΔT) is from 67°C to 98°C, a change of 31°C. Plugging these values into the formula gives:
c = 7.2 J / (7.9 g × 31°C)
C = 0.0292 J/g°C
This value represents the specific heat capacity of the unknown substance. To identify the substance, you would refer to a table such as Table 9.1 (or Table 5.1 as mentioned). If the specific heat capacity matches one of the substances on the table, you can then determine its likely identity.