Answer:
Explanation:
A catalyst is a <em>substance that increases the rate of a reaction by lowering the activation energy</em>. It does so by providing an alternative reaction pathway. The catalyst may react to form an intermediate with the reactant, but it is regenerated in a subsequent step so it is not consumed in the reaction. A catalyst speeds up a reaction by providing a set of elementary steps with more favorable kinetics than those that exist in its absence.
Answer:
It has a different value at different temperatures.
Explanation:
For any system in equilibrium, the molar concentration of all the species on the right hand side are related to the molar concentrations of those at the left side by a constant known as the equilibrium constant.
The equilibrium is a constant at a given temperature as it is temperature dependent.
A change in temperature of an equilibrium system shifts the system to a new equilibrium point. A rise in temperature actually shifts equilibrium position to the direction that absorbs heat and vice versa.
The shift in equilibrium as a result of temperature change is actually a change in the value of the equilibrium constant. Equilibrium constant is represented as
The derivation of the equilibrium constant is based on the Law of Mass Action which states: the rate of a chemical reaction is proportional to the product of the concentrations of the reacting substances.
Answer: 61%
The reaction equation should be
CaF2 + H2SO4 → 2HF + CaSO4
For every 1 molecule CaF2 used, there will be 2 molecules of HF formed. The molecular mass of CaF2 is 78/mol while the molecular mass of HF is 20g/mol. If the yield is 100%, the amount of HF formed by 112g CaF2 would be: 112g/(78g/mol) * 2 * (20g/mol)=57.43g
The percentage yield of the reaction would be: 35g/57.43g= 60.94%
Answer
Dmitri Mendeleev Explanation:The modern periodic tables is credited primarily to the russian chemist Dmitri Mendeleev. Mendeleev's table is based on the periodic law, which states that when elements are arranged in order of increasing mass, their properties recur periodically.