Answer:
4.13×10²⁷ molecules of N₂ are in the room
Explanation:
ideal gases Law → P . V = n . R . T
Pressure . volume = moles . Ideal Gases Constant . T° K
T°K = T°C + 273 → 20°C + 273 = 293K
Let's determine the volume of the room:
18 ft . 18 ft . 18ft = 5832 ft³
We convert the ft³ to L → 5832 ft³ . 28.3L / 1 ft³ = 165045.6 L
1 atm . 165045.6 L = n . 0.082 L.atm/mol.K . 293K
(1 atm . 165045.6 L) / 0.082 L.atm/mol.K . 293K = n
6869.4 moles of N₂ are in the room
If we want to find out the number of molecules we multiply the moles by NA
6869.4 mol . 6.02×10²³ = 4.13×10²⁷ molecules
We can use the heat equation,
Q = mcΔT
where Q is the amount of energy transferred (J), m is the mass of the substance (kg), c is the specific heat (J g⁻¹ °C⁻¹) and ΔT is the temperature difference (°C).
Q = 11.2 kJ = 11200 J
m = <span>145 g
</span>c = ?
ΔT = (67 - 22) °C = 45 °C
By applying the formula,
11200 J = 145 g x c x 45 °C
c = 1.72 J g⁻¹ °C⁻¹
Hence, specific heat of benzene is 1.72 J g⁻¹ °C⁻¹.
The energy of 393 kJ is released as heat. Then, the container will experience an increase of temperature and, given that it is sealed, also an increase of pressure.
The increase of temperature results from the heat developed during the reaction.
The increase of pressure results from the fact that that the solid carbon will become gaseuos carbon dioxide. This gas will occupy a larger volume than the solid carbon and also this elevation of the temperature will make the pressure of the gas inside the container increase.
Answer:
B. liquid to gas
Explanation:
Matter exists in 3 different states:
- Solid: in solids, particles in the substance are tightly bond to each other through strong intermolecular forces. Therefore, they can only vibrate around their fixed position, but they cannot move freely: as a result, the distance between the particles is the smallest among the 3 states of matter.
- Liquid: in a liquid, particles are able to slide past each other, however there are still intermolecular forces keeping them not too far from each other. As a result, in liquids, particles are on average more distance from each other compared to solids.
- Gas: in a gas, particles are completely free to move, as the intermolecular forces between them are negligible. As a result, in gases, the distance between molecules is the greatest, compared with solids and liquids.
Therefore, the phase changes in which the average distance between molecules increases is:
B. liquid to gas
