Sound travels through gases faster than it travels through liquids
Answer:
a mixture is a material made up of two or more different substances which are physically combined.
Sugar and water are made with tiny particles. They are both made from molecules and atoms.
Answer:
∆H° rxn = - 93 kJ
Explanation:
Recall that a change in standard in enthalpy, ∆H°, can be calculated from the inventory of the energies, H, of the bonds broken minus bonds formed (H according to Hess Law.
We need to find in an appropiate reference table the bond energies for all the species in the reactions and then compute the result.
N₂ (g) + 3H₂ (g) ⇒ 2NH₃ (g)
1 N≡N = 1(945 kJ/mol) 3 H-H = 3 (432 kJ/mol) 6 N-H = 6 ( 389 kJ/mol)
∆H° rxn = ∑ H bonds broken - ∑ H bonds formed
∆H° rxn = [ 1(945 kJ) + 3 (432 kJ) ] - [ 6 (389 k J]
∆H° rxn = 2,241 kJ -2334 kJ = -93 kJ
be careful when reading values from the reference table since you will find listed N-N bond energy (single bond), but we have instead a triple bond, N≡N, we have to use this one .
The equation relating velocity and wavelength is written below:
v = λf
where λ is the wavelength in m while f is frequency in 1/s.
Let's determine first the frequency from the speed of light:
c = distance/time, where c is the speed of light equal to 3×10⁸ m/s
3×10⁸ m/s = (300 mm)(1 m/1000 mm)/ time
time = 1×10⁻⁹ seconds
Since f = 1/t,
f = 1/1×10⁻⁹ seconds = 10⁹ s⁻¹
Thus,
v = (795×10⁻⁹ m)(10⁹ s⁻¹)
v = 795 m/s
