Which is not true for a catalyst?

(A) It appears as a reactant in the net chemical reaction
(B) It causes a lowering of the activation energy
(C) It can be homogeneous or heterogeneous
(D) It increases the rate of a chemical rate of a reaction

(A) It appears as a reactant in the net chemical reaction

Explanation:

A catalyst is  A substance that speed up the chemical reaction without its self being consumed in the reactants or the products.It does this by lowering the activation energy of the reaction by speeding up the rate of reaction.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"