Answer:
Explanation: The lowest pressure in a laboratory is 4.0×10^-11Pa
Using Ideal gas equation
PV = nRT
P= 4.0×10^-11Pa
V= 0.020m^3
T= 20+273= 293k
n=number of moles = m/A
Where m is the number of molecules and A is the Avogradro's number=6.02×10²³/mol
R=8.314J/(mol × K)
PV= m/A(RT)
4.0×10^-11 ×0.020 = m/6.02×10²³(8.314×293)
m = 4.0×10^-11×0.020×6.02×10^23 / (8.314×293)
m = 1.98×10^8 molecules
Therefore,the number of molecules is 1.98×10^8
Answer:
<u>only sodium chloride compounds</u> MOST LIKELY products of the reaction between sodium metal and chlorine gas.
Correct answer - C
Explanation:
A solid sodium metal reacts with gaseous form of chlorine gas to form a solid sodium chloride.
This formation of sodium chloride arises due to transfer of one valence electron from sodium to chlorine atom and the both atoms get stable octet electronic configuration.
As a result, an ionic compound solid sodium chloride is formed.
The chemical reaction of formation sodium chloride is as follows.

Therefore, <u>only sodium chloride compounds</u> MOST LIKELY products of the reaction between sodium metal and chlorine gas.
The black lines in the Sun's spectrum are caused by gases on, or above, the Sun's surface that absorb some of the emitted light.
Lower the melting point
Explanation:
Salts helps to melt road by lowering the melting point. It acts as an impurity and generally, impurities low the melting point of substances.
Salts are used as an antifreeze.
- Water freezes at 0°C and forms ice/snow which can impede human and vehicular movement.
- When salt is added, it causes the depression of the freezing point by lowering it further.
- The freezing point is pegged back at -6°C.
- This way it takes more low temperature to freeze the water.
- The salt acts as an impurity and causes the depression of melting point and widening of the melting range.
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75.2 grams....????? Maybe