Answer:
The atoms in the first period have electrons in 1 energy level. The atoms in the second period have electrons in 2 energy levels. The atoms in the third period have electrons in 3 energy levels. The atoms in the fourth period have electrons in 4 energy levels.
2) is the answer. graphite and diamonds possess the same molecular structes however the bonds and structures of diamonds are considerably stronger and more tightly packed respectively
Given :
10 gram sample of propane( C₂H₈ ).
To Find :
The number of moles of propane in given sample.
Solution :
Molecular mass of propane, M = (2 × 12) + ( 1 × 8 ) gram/mol
M = 32 gram/mol
We know, number of moles is given by :
Number of moles, n = m/M
n = 10/32 mol
n = 0.3125 mol
Therefore, number of moles in given sample is 0.3125 mol.
Answer:
0.0300 moles of H₂
Explanation:
The original equation is PV = nRT. We need to change this to show moles (n).
n = 
It's important to convert your values to match the constant (r) in terms of units.
30.0 kPa = 0.296 atm
2500 mL = 2.50 L
27 °C = 300 K
Now, plug those values in to solve:
n = 
- for the sake of keeping the problem clean, I didn't include the units but you should just to make sure everything cancels out :)
Finally, you are left with n = 0.0300 moles of H₂
C. Physical changes do not change the identity of a substance, only the physical appearance such as shape or form. If you break a pencil in half, it is still composed of the same material and therefore keeps its identity as the substance it was before the physical change. Phase changes, such as ice melting, is also a physical change because it changes form. But ice is still made of H20 just like water and steam are comprised of H20.
