Explanation:
As per the Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
Hence, according to this law the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
..........(1)
..............(2)
The final reaction is as follows:
.............(3)
Therefore, adding (1) and (2) we get the final equation (3) and value of 
at 298 K will be as follows.
= 
+ 
= -314 kJ + (-80) kJ
= -394 kJ
Thus, we can conclude that 
at 298 K for the given process is -394 kJ.
The answer is A. 1350
(ALL NUMBERS Except the grams is given from the equation)
18.21mol HNO3/1 * 1mol MgN206/2mol/ 2mol HNO3 * (molar mass-->)148.30 MgN206/ 1mol MgN2O6
You multiply 18.21HNO3* 1mol MgN2O6 * 148.30MgN2O6
Then divide it by the 2mol HNO3 to get 1350
We can use two equations to solve this.
(1) - E = hf
E = Energy (J)
h = plank's constant (6.63 × 10⁻³⁴ J s)
f = frequency (Hz)
(2) - v = fλ
v = velocity of the wave (m/s)
f = frequency (Hz)
λ = wavelength (m)
the λ for the given wave is 625nm (625 x 10⁻⁹ m) and the velocity of the wave is equal to speed of light (3 x 10⁸ m/s) since the wave is a light.
hence we can find the frequency of the wave by using (2) formula.
3 x 10⁸ m/s = f x 625 x 10⁻⁹ m
f = 4.8 x 10¹⁴ Hz
by using calculated frequency and (1) formula, we can find the energy of the wave.
E = 6.63 × 10⁻³⁴ J s x 4.8 x 10¹⁴ Hz
E = 3.18 x 10⁻¹⁹ J
The energy of wave is less than energy needed to eject an electron.
Hence, the metal does not eject electron.
Fats release more energy per gram that proteins. when burned a gram of fat releases 9 calories, while one gram of protein releases about 4 calories. Fats release about twice as much energy per gram than protein. Proteins are essential in numerous body functions and processes so this molecule is not usually metabolized for energy.
Answer:
C. pieces of hair found at the crime scene.
Explanation:
using the pieces of hair, you can get the DNA of the person. This will give u a better lead in solving the crime.
Hope it helps u ....
