Problem: To determine whether a shiny gold-colored rock is actually gold, a chemistry student decides to measure its heat capacity. She first weighs the rock and finds it has a mass of 4.0 g . She then finds that upon absorption of 54.6 J of heat, the temperature of the rock rises from 25 oC to 56 oC.SubstanceSpecific heatcapacity, Cs (J/(g oC))*ElementsLead0.128Gold0.128Silver0.235Copper0.385Iron0.449Aluminum0.903CompoundsEthanol2.42Water4.18MaterialsGlass (Pyrex)0.75Granite0.79Sand0.84* At 298 K.Determine whether the value is consistent with the rock being pure gold by referring to the table.

FREE Expert Solution

We’re being asked to determine if the rock is pure gold by referring to the table of substances and their specific heat capacity.


We will determine the specific heat capacity of the rock from the given values then refer to the table to identify the rock.


Thspecific heat capacity can be calculated using the following equation for the heat released or absorbed (q):

q = mcT

where 

m = mass of water (in grams)

c = specific heat capacity of water

ΔT = change in temperature = final T – initial T.


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Problem Details

To determine whether a shiny gold-colored rock is actually gold, a chemistry student decides to measure its heat capacity. She first weighs the rock and finds it has a mass of 4.0 g . She then finds that upon absorption of 54.6 J of heat, the temperature of the rock rises from 25 oC to 56 oC.


SubstanceSpecific heat
capacity, Cs 
(J/(g oC))*
Elements
Lead0.128
Gold0.128
Silver0.235
Copper0.385
Iron0.449
Aluminum0.903
Compounds
Ethanol2.42
Water4.18
Materials
Glass (Pyrex)0.75
Granite0.79
Sand0.84
* At 298 K.


Determine whether the value is consistent with the rock being pure gold by referring to the table.

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Calorimetry concept. You can view video lessons to learn Calorimetry. Or if you need more Calorimetry practice, you can also practice Calorimetry practice problems.