When a substance receives 800 cal of heat, its temperature increases by 20°C. If the specific heat of the substance is 0.02cal/(gm°C) then find the mass of the substance in kilogram?
Answers
Explanation:
Specific heat represents the amount of heat required to change a unit mass of a substance by one degree Celsius. This is expressed mathematically as:
q=m⋅c⋅ΔT, where
q - the amount of heat supplied;
m - the mass of the substance;
c - the respective substance's specific heat;
ΔT - the change in temperature.
So, if we want to determine the units for specific heat, we'll just isolate the term in the above formula to get
c=qm⋅ΔT. Since heat is measured in Joules (J), mass in grams (g), and temperature in degree Celsius (C), we can determine that
c=Jg⋅∘C.
Therefore, specific heat is measured in Joules per g times degree Celsius.
Stefan V. · 4 · Dec 29 2014
How can specific heat be used to identify substances?
Specific heat is an intensive property (like density, color, etc.) that does not depend on the amount of a substance present. This allows substances to be identified using their specific heat.
Imagine an unknown metal of known mass is heated to a known temperature. The heated metal can then be placed into a sample of water for which the volume (and therefore mass since 1mL=1g) and temperature are known.
The amount of energy (Q) transferred to the water can be calculated by using the equation Qw=mwCΔTw since the mass (m) and ∆T(temp change) can be measured.
This allows for a calculation of the C value for the metal since the head gained (Qw) of the water will equal the heat lost by the metal (Qm).
The C value for the metal allows the metal to be identified.
A listing of C values for metals can be found here:
http://www2.ucdsb.on.ca/tiss/stretton/database/Specific_Heat_Capacity_Table.html
mrpauller.weebly.com · 17 · Apr 3 2014
Questions
Answer:
c = specific heat capacity
q = heat energy
m = mass
t = temperature
c = q / m * t
0.02 = 800 / m * 20
m = 800 / 20 *0.02
m = 2000g
m = 2 kg