B. increase; decrease or are absent
In a liquid, the particles move around more than a solid, but way less than in a gas because there isn't that much space between particles.
When matter is a gas, the particles tend to move in a larger area and they tend to get very far away from each other. So, the space between particles increase and the attraction forces decrease.
Appropriate units for the speed of a chemical reaction, the reaction rate, are M/s
Answer:

Explanation:
Range = Highest value - Lowest value
A 'soft solder' melts between 183 °C and 212 °C.
Melting range of a 'soft solder' = 
A 'hard solder' melts between 620 °C and 680 °C.
Melting range of a 'hard solder' = 
So,
Difference in melting ranges = Melting range of a 'hard solder' - Melting range of a 'soft solder' = 
Answer: The correct answer is option B)
in the synthesis of cryolite for aluminum production.
Explanation:
Hydrogen fluoride (HF) is used in synthesis of cryolite for aluminum production.
HF is a gas that dissolves in water to form hydrofluoric acid. However, HF also react with halogenated alkanes like trichloromethane CHCl3 to form organofluorine compounds that serves as precursors in the synthesis of cryolite, an Ore from which aluminum is produced
Answer:
it means compound A is <u>less</u> polar than compound B
Explanation:
It is sure that the more polar the solvent, the faster compounds elute, regardless of the compounds polarity. This means changing the solvent polarity cannot change the order compounds elute from a TLC or column. This may seem non intuitive, as it would seem that a polar solvent would move a polar compound farther than a nonpolar compound.