Answer:
Here it would be A,B and C because all the examples are violating safety precautions. They are all examples of un safe signs.
Hope this helps
Explanation:
Answer: The volume of 0.640 grams of
gas at Standard Temperature and Pressure (STP) is 0.449 L.
Explanation:
Given: Mass of
gas = 0.640 g
Pressure = 1.0 atm
Temperature = 273 K
As number of moles is the mass of substance divided by its molar mass.
So, moles of
(molar mass = 32.0 g/mol) is as follows.
![No. of moles = \frac{mass}{molar mass}\\= \frac{0.640 g}{32.0 g/mol}\\= 0.02 mol](https://tex.z-dn.net/?f=No.%20of%20moles%20%3D%20%5Cfrac%7Bmass%7D%7Bmolar%20mass%7D%5C%5C%3D%20%5Cfrac%7B0.640%20g%7D%7B32.0%20g%2Fmol%7D%5C%5C%3D%200.02%20mol)
Now, ideal gas equation is used to calculate the volume as follows.
PV = nRT
where,
P = pressure
V = volume
n = no. of moles
R = gas constant = 0.0821 L atm/mol K
T = temperature
Substitute the values into above formula as follows.
![PV = nRT\\1.0 atm \times V = 0.02 mol \times 0.0821 L atm/mol K \times 273 K\\V = 0.449 L](https://tex.z-dn.net/?f=PV%20%3D%20nRT%5C%5C1.0%20atm%20%5Ctimes%20V%20%3D%200.02%20mol%20%5Ctimes%200.0821%20L%20atm%2Fmol%20K%20%5Ctimes%20273%20K%5C%5CV%20%3D%200.449%20L)
Thus, we can conclude that the volume of 0.640 grams of
gas at Standard Temperature and Pressure (STP) is 0.449 L.
Answer:
The rusting of iron is spontaneous at low temperatures.
Explanation:
The given chemical reaction is:
4Fe(s) + 3O2(g) ----> 2Fe2O3(s) [rust]
The rusting of iron is a chemical reaction in which iron reacts with oxygen in presence of moisture and forms iron oxide.
This reaction takes place in a faster rate when there is low temperatures in the atmosphere.
When temperature is low, the moisture in the atmosphere is more and hence, rate of rusting is more.