Answer:
Option 3. The catalyst does not affect the enthalpy change (
) of a reaction.
Explanation:
As its name suggests, the enthalpy change of a reaction (
) is the difference between the enthalpy of the products and the reactants.
On the other hand, a catalyst speeds up a reaction because it provides an alternative reaction pathway from the reactants to the products.
In effect, a catalyst reduces the activation energy of the reaction in both directions. The reactants and products of the reaction won't change. As a result, the difference in their enthalpies won't change, either. That's the same as saying that the enthalpy change
of the reaction would stay the same.
Refer to an energy profile diagram. Enthalpy change of the reaction
measures the difference between the two horizontal sections. Indeed, the catalyst lowered the height of the peak. However, that did not change the height of each horizontal section or the difference between them. Hence, the enthalpy change of the reaction stayed the same.
Wouldn't be a then not c if both were solutions.
Answer:
If you left your aqueous sodium sulfite solution open on the side, atmospheric oxygen would cause the chemical change, the water would hydrate the new compound and the slow evaporation of water would give you lovely large crystals of Na2SO4 without you having to do anything!
Answer:
323.99 mg
Explanation:
We need to find the mass of the aspirin tablet that contains 5.0 grains of aspirin.
1 pound = 7000 grains


We know that, 1 pound = 453.592 grams
Also, 1 pound = 453592 mg

Hence, 4 grains of aspirin contains 323.99 mg.