Answer:
mass HF = 150.05 g
Explanation:
- SiO2(s) + 4HF(g) → SiF4(g) + 2H2O(l)
⇒ Q = (ΔH°rxn * mHF) / (mol HF * MwHF )
∴ MwHF = 20.0063 g/mol
∴ mol HF = 4 mol
∴ ΔH°rxn = - 184 KJ
∴ Q = 345 KJ
mass HF ( mHF ):
⇒ mHF = ( Q * mol HF * MwHF ) / ΔH°rxn
⇒ mHF = ( 345 KJ * 4mol HF * 20.0063 g/mol ) / 184 KJ
⇒ mHF = 150.05 g HF
Well.. if ur going down a ramp, friction beat gravity, right....??? I guess, I I have an idea hahha
Answer:
The enthalpy change in the the reaction is -47.014 kJ/mol.
Explanation:

Volume of water in calorimeter = 22.0 mL
Density of water = 1.00 g/mL
Mass of the water in calorimeter = m

Mass of substance X = 2.50 g
Mass of the solution = M = 2.50 g + 22 g = 24.50 g
Heat released during the reaction be Q
Change in temperature =ΔT = 28.0°C - 14.0°C = 14.0°C
Specific heat of the solution is equal to that of water :
c = 4.18J/(g°C)


Heat released during the reaction is equal to the heat absorbed by the water or solution.
Heat released during the reaction =-1.433 kJ
Moles of substance X= 
The enthalpy change, ΔH, for this reaction per mole of X:

It depends on what unit/subject you're looking at.
Because in physics, I know that if you are considering Newton's theory of particles, all particles technically go in a straight line from the original direction. BUT, if you're looking at the Wave of the Particle theory, then you would assume that particles do not necessarily follow the above b/c they follow the properties of a wave...
Sucrose is insoluble in dichloromethane because dichloromethane is not a polar solvent.
Sucrose is soluble in water because the molecules of sucrose has the ability to react with the molecules of water and thereby forming hydrogen bond which enhance the dispersion of sucrose in the water.
Sugar can not react in a similar way with dichloromethane because they do not possess chemical species that can react together to form bonds. Thus, sugar is a polar substance which can not dissolve in a non-polar solvent.