Which increases the rate of a chemical reaction? a. a catalyst b. a higher volume c. a lower pressure d. a lower temperature

A catalyst will increase the rate of a chemical reaction by changing the reaction mechanism so that the reaction has a lower activation energy.  

a higher volume will decrease the concentrations which will intern decrease the number of collisions which will slow down the rate of the reaction since collisions between reactants are what make reactions happen.  A lower temperature causes the molecules to slow down thereby lowering the collision rate which will lower the reaction rate.  A lower pressure will lower the number of collisions which will intern result in a lower reaction rate (this can be thought of as a lower concentration since lower pressures involve less gas per unit volume)

A. A catalyst because it increases the time that it takes to happen

Answerit curves up and levels out.explanationwe assume that the container contains absolutely no ammonia to begin with as it states that "nitrogen gas and hydrogen gas" react to "produce ammonia."at dynamic equilibrium, the product and reactant concentrations are equal.this means that, starting from a concentration of zero, [nh₃] must curve "up" from zero and then level out to a constant concentration.

Molarity is moles of solute over liters of solution. idk if that is what you are talking about, but you can convert moles of solute to grams of solute using dimensional analyzes by using molar mass found on the periodic table.