The initial temperature is 137.34 °C.
<u>Explanation:</u>
As the specific heat formula says that the heat energy required is directly proportional to the mass and change in temperature of the system.
Q = mcΔT
So, here the mass m is given as 23 kg, the specific heat of steel is given as c = 490 J/kg°C and the initial temperature is required to find with the final temperature being 140 °C. Also the heat energy required is 30,000 J.
ΔT =
ΔT =
Since the difference in temperature is 2.66, then the initial temperature will be
Final temperature - Initial temperature = Change in temperature
140-Initial temperature = 2.66
Initial temperature = 140-2.66 = 137.34 °C
Thus, the initial temperature is 137.34 °C.
It can be anything with a big heat capacity like water
Answer: 1. halve
2. halve
3. double
Explanation:
The relationship between wavelength and energy of the wave follows the equation:
E= energy
= wavelength of the wave
h = Planck's constant
c = speed of light
Thus as wavelength and energy have inverse realation, when wavelength will halve , energy will double.
2. The between wavenumber and energy of the wave follows the equation:
E= energy
= wavenumber of the wave
h = Planck's constant
c = speed of light
Thus as wavenumber and energy have direct relation, when wavenumber will halve , energy will be halved.
3. The relationship between energy and frequency of the wave follows the equation:
where
E = energy
h = Planck's constant
= frequency of the wave
Thus as frequency and energy have direct realation, when frequency will double , energy will double.
Answer:
The reaction is exothermic.
Explanation:
Sodium chloride and prussic acid are formed
NaCN+HCl→NaCl+HCN
