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.

5 0

3 years ago

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Water is flowing in a pipe with a mass flow rate of 100.0 lb/h (M water H,O=18.016). What is the (i) Molar flow rate of H20 (gmo

Arada [10]

Answer:

i) 0,7 molH20/s

ii)11,2 g O/s

iii)1,4 g H/s

Explanation:

i) To find the molar flow rate of water, we just convert the mass of water to moles of water using its molecular weight(g/mol) and changing to the proper units (lb to grames and hours to seconds):

$100 \frac{lb}{h}*\frac{453,5g}{1 lb}*\frac{1molH20}{18,016g}*\frac{1h}{3600s}=0,7\frac{molH20}{s}$

ii) Now we just consider the oxygen in the water stream (for 1 mole of water there is 1 mole of oxygen):

$100\frac{lb}{h} *\frac{453,5g}{1lb}*\frac{1 molH20}{18,016g}*\frac{1molO}{1molH20}*\frac{16gr}{1molO}*\frac{1h}{3600s}=11,2\frac{gO}{s}$

iii)Just considering the hydrogen in the stream (for 1 mole of water there is 2 moles of hydrogen):

$100\frac{lb}{h} *\frac{453,5g}{1lb}*\frac{1 molH20}{18,016g}*\frac{2molH}{1molH20}*\frac{1gr}{1molH}*\frac{1h}{3600s}=1,4\frac{gH}{s}$

3 0

2 years ago