Answer: As temperature increases, the number of collisions increases and the energy of the collisions increases.
Explanation:
According to collision theory, for a reaction to take place it is necessary to have collisions between the reacting species or atoms.
A collision will only be effective if species coming together have a certain minimum value of internal energy equal to the activation energy of the reaction.
More is the number of collisions taking place in a chemical reaction more will be the kinetic energy of its molecules. As kinetic energy is the energy acquired due to motion of atoms or a substance.
Also, collisions increases with increase in temperature as:

Kinetic energy is directly proportional to temperature. So, more is the temperature more will be energy of molecules.
Thus, we can conclude that as temperature increases, the number of collisions increases and the energy of the collisions increases.
 
        
             
        
        
        
Answer:
Halogens
Explanation:
From the given choices, the halogens will have the smallest radius within the same period. 
The size of an atom is estimated by the atomic radius. This is taken as half of the inter-nuclear distance between two covalently bonded atoms of non-metallic elements or half of the distance between two nuclei in the solid state. 
- Across a period in the periodic table, atomic radii decrease progressively from left to right. 
- Down a group from top to bottom, atomic radii increase progressively due to the addition of successive shells. 
Since halogen is the right most group from the choices given, it will have the smallest radius. 
 
        
             
        
        
        
Unfortunately the data provided doesn't include the DENSITY of the ammonium chloride solution and molarity is defined as moles per volume. So without the density, the calculation of the molarity is impossible. But fortunately, there are tables available that do provide the required density and for a 20% solution by weight, the density of the solution is 1.057 g/ml.  
So 1 liter of solution will mass 1057 grams and the mass of ammonium chloride will be 0.2 * 1057 g = 211.4 g. The number of moles will then be 211.4 g / 53.5 g/mol = 3.951401869 mol. Rounding to 3 significant digits gives a molarity of 3.95.  
Now assuming that your teacher wants you to assume that the solution masses 1.00 g/ml, then the mass of ammonium chloride will only be 200g, and that is only (200/53.5) = 3.74 moles.   
So in conclusion, the expected answer is 3.74 M, although the correct answer using missing information is 3.95 M.
        
                    
             
        
        
        
Answer:
It is not a gas because its particles do not have large spaces between them.
Explanation:
Solids and liquids have a lot of particles with few spaces between them. Also, gas particles move rapidly in each direction.
 
        
             
        
        
        
When uranium<span> comes in contact with oxygen in the air, it rusts, just like iron does, but </span>uranium<span> rust is black and not red. Like other heavy </span>atoms <span>such as iron, </span>uranium atoms<span> have more neutrons than they do protons. Not all </span>uranium atoms<span> have the </span>same<span> number of neutrons.</span>