Answer:
ΔH = +26.08 kJ/mol
Explanation:
The change in enthalpy (ΔH) is given in J/mol, and can be calculated for dissolution by the equation:
ΔH = m(water)*Cp*ΔT/n(solute)
The mass of water is the density multiplied by the volume
m = 1g/mL * 25.0mL = 25.0 g
The number of the moles is the mass divided by the molar mass. Knowing the molar masses of the elements:
N = 14 g/mol x 2 = 28
H = 1 g/mol x 4 = 4
O = 16 g/mol x 3 = 48
NH₄NO₃ = 80 g/mol
n = 1.25/80 = 0.015625 mol
So,
ΔH = 25*4.18*(25.8 - 21.9)/0.015625
ΔH = 26,083.2 J/mol
ΔH = +26.08 kJ/mol
Hey there !
The answer is C. build up of electrical charges by friction
Static electricity is a stationary electric charge, typically produced by friction, which causes sparks or crackling or the attraction of dust or hair.
Hope this helps !
The answer is critical mass with no doub t
The fragrant organic compounds found in many flowers that contain a carbonyl group bonded to a carbon atom and a hydrogen atom are called aldehydes.
Answer:
The correct answer is option D.
Explanation:
A fuel cell is defined as the electrochemical cell which converts the chemical energy of a fuel (often used hydrogen) and an oxidizing agent (often used oxygen) into electrical energy via a pair of redox reactions.
The reactions which occur in hydrogen-oxygen fuel cell are:
At cathode: 
At anode: 
As we can see that reaction of hydrogen gas with oxygen gas gives us the water as a product which can be used for other things and it also doesn't pollutes environment.
