Question

This means that the steel bar lost 14900 J of thermal energy. What is the change in temperature of the steel bar? Recall that the steel decreases in temperature, and use the value of 0.49 J/g•°C as the specific heat capacity of steel. The video shows the mass of the steel to be 40.7 g.

Answer 1

Answer:

$\Delta T=-747.13^0C$

Explanation:

Hello,

In this case, the heat is related with the change in the temperature via the heat capacity and the involved mass as shown below:

$Q=mCp\Delta T$

Now, as it is stated that there is an amount of lost heat, such value turn out negative implying that the final temperature is lower than the initial one, in such a way, one computes $\Delta T$ as a measure of the change in the temperature as follows:

$\Delta T=\frac{Q}{mCp} =\frac{-14900J}{0.49J/(g^0C)*40.7g}\\ \Delta T=-747.13^0C$

Best regards.

Answer 2

Answer:

ΔT=-747,13°C

Explanation:

Sensible heat is the amount of thermal energy that is required to change the temperature of an object, the equation for calculating the heat change is  given by:

Q=msΔT

where:

• Q, heat that has been absorbed or realeased by the substance [J]
• m, mass of the substance [g]
• s, specific heat capacity [J/g°C] (
• ΔT, changes in the substance temperature [°C]

To solve the problem, we clear ΔT of the equation and then replace our data:

Q=msΔT

ΔT=Q/ms

Δ$T=\frac{-14900 J}{40,7g*0,49\frac{J}{gC} }=-747,13$°C

(Note that Q=-14900 J because there is a LOST of thermal energy)

Thus, the change in temperature of the steel bar is -747,13°C, meaning that the temperature of the bar decreases.