Answer: Because new substances are formed.
Explanation: A chemical property is any of a material's properties that becomes evident during, or after, a chemical reaction; that is, any quality that can be established only by changing a substance's chemical identity. Once a chemical change occurs it cannot be undone due to the change in chemical identity. The creation of a new substance is not reversible.
The layer that we live in is the Troposphere.
Hope this answer is correct.
Answer:
Its final temperature is 25.8 °C
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
There is a direct proportional relationship between heat and temperature. The constant of proportionality depends on the substance that constitutes the body as on its mass, and is the product of the specific heat by the mass of the body. So, the equation that allows calculating heat exchanges is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation (ΔT=Tfinal-Tinitial)
When a body transmits heat there is another that receives it. This is the principle of the calorimeter. Then the heat released by the compound will be equal to the heat obtained by the calorimeter.
In this case, you know:
- c= 3.55

- m=1.20 kg= 1200 g (1 kg=1000 g)
- Tfinal= ?
- Tinitial= 22.5 °C
Replacing:

Solving:

3.3=Tfinal - 22.5 C
3.3 + 22.5=Tfinal
Tfinal= 25.8 °C
<u><em>Its final temperature is 25.8 °C</em></u>
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