Answer:
C) 43,2°C
Explanation:
<em>Sensible heat</em> 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=890 [J],
m=16,6 [g],
s=2,74 [J/g°C]
Q=msΔT.......................ΔT=Q/ms
Δ
°C
As:
ΔT=Tfinal-Tinitial
Tfinal=ΔT+Tinitial
Tfinal=21,7+21,5=43,2°C
The final temperature of the ethanol is 43,2°C.
Answer:
total time = 304.21 s
Explanation:
given data
y = 50% = 0.5
n = 1.1
t = 114 s
y = 1 - exp(-kt^n)
solution
first we get here k value by given equation
y = 1 - 
...........1
put here value and we get
0.5 = 1 - e^{(-k(114)^{1.1})}
solve it we get
k = 0.003786 = 37.86 × 
so here
y = 1 -
1 - y =
take ln both side
ln(1-y) = -k × 
so
t = ![\sqrt[n]{-\frac{ln(1-y)}{k}}](https://tex.z-dn.net/?f=%5Csqrt%5Bn%5D%7B-%5Cfrac%7Bln%281-y%29%7D%7Bk%7D%7D)
.............2
now we will put the value of y = 87% in equation with k and find out t
t = ![\sqrt[1.1]{-\frac{ln(1-0.87)}{37.86*10^{-4}}}](https://tex.z-dn.net/?f=%5Csqrt%5B1.1%5D%7B-%5Cfrac%7Bln%281-0.87%29%7D%7B37.86%2A10%5E%7B-4%7D%7D%7D)
total time = 304.21 s
Mass and chemical composition
Answer:
Explanation:
The determination of any further properties requires the knowledge of two independent properties. (Temperature and specific volume in this case). The specific volumes for saturated liquid and vapor at 140 °C are, respectively:
Since 
, it is a liquid-vapor mixture. The quality of the mixture is:
The specific enthalpies for saturated liquid and vapor at 140 °C are, respectively:
The specific enthalpy is:
Answer:
Time required for iron rod surface temperature to cool to 200°C is 250 seconds.
Explanation:
