Question about this formula (Q = m.C.ΔT)

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In summary, there is a direct proportionality relationship between the quantity of heat (Q) and the specific heat (C). This means that as the value of C increases, more heat is necessary to produce a temperature change. An inversely proportional relationship would have either C or the temperature change (ΔT) in the denominator of a fraction. This can be seen in the example of travel time, where it is directly proportional to distance and inversely proportional to speed. Therefore, Q is directly proportional to C, not inversely proportional.
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fabrc
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Quantity of heat (Q) is directly proportional to specific heat (C)?

I thought that they would be inversely proportional because the higher the value of C, more heat is necessary to make a variation of temperature but somehow it seems wrong.

Help please! :confused:

Thanks!
 
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fabrc said:
Quantity of heat (Q) is directly proportional to specific heat (C)?

I thought that they would be inversely proportional because the higher the value of C, more heat is necessary to make a variation of temperature but somehow it seems wrong.

The amount of heat needed to produce a temperature change of ##\Delta{T}## in a mass of ##m## of a substance with specific heat ##C## is given by ##\Delta{Q}=mC\Delta{T}##, right? The higher the value of ##C##, the more heat will be necessary, just as you say. That's a direct proportionality relationship by definition . An inversely proportional relationship would have either ##C## or ##\Delta{T}## in the denominator of a fraction.

Another example: travel time is directly proportional to distance and inversely proportional to speed (all else being the same, the greater the distance the greater the travel time and the greater the speed the less the travel time). These quantities are related by ##T=d/s## where ##T## is the travel time, ##d## is the distance traveled, and ##s## is the speed. Look at which one appears in the denominator of a fraction.
 
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I got it. Thanks, Nugatory!
 

FAQ: Question about this formula (Q = m.C.ΔT)

1. What does each variable in the formula represent?

In this formula, Q represents the amount of heat transferred, m represents the mass of the substance, C represents the specific heat capacity of the substance, and ΔT represents the change in temperature.

2. How is this formula used in science?

This formula is commonly used in science to calculate the amount of heat transferred during a physical or chemical change. It is also used to determine the specific heat capacity of a substance.

3. What is the unit of measurement for each variable in this formula?

The unit for Q is joules (J), the unit for m is grams (g), the unit for C is joules per gram per degree Celsius (J/g°C), and the unit for ΔT is degrees Celsius (°C).

4. Can this formula be used for any substance?

Yes, this formula can be used for any substance as long as the specific heat capacity is known. However, it is most commonly used for liquids and solids.

5. How does this formula relate to the Law of Conservation of Energy?

This formula is derived from the Law of Conservation of Energy, which states that energy cannot be created or destroyed, only transferred or transformed. In this formula, the amount of heat transferred (Q) is equal to the change in thermal energy (m.C.ΔT) of the substance.

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