Question

In the reaction of Mg (s) + 2 HCl (aq) arrow MgCl2 (aq) + H2 (g), which of the following would decrease the rate of the forward reaction?

Increasing the mass of magnesium

Changing HCl solution from 0.500 moles in 0.5 liters to 0.500 moles in 1.5 liters

Decreasing the pressure of the system

Increasing the surface area of the magnesium solid

Answer 1

@rayep12 @Kevin @jonathan34, I need help in here.

Answer 2

well,

Equilibrium just tells you which way the chemical reaction wants to go. In your equation if they would of wrote it : MgCl2 (aq) + H2 (g) + heat --> 2 HCl (aq) + Mg(s), instead of the way they did, it would be easier to see because we are always accustomed to the reactants being on the left side and the products on the right.

Because suppose in the equation above , I wanted to make HCl and get magnesium metal. If I asked you what chemicals to get to be able to make it you would list it in the way I just wrote it above. The trouble is the way the chemicals react it is favorable to react HCl and Mg to get the products of MgCl2 and H2 with a lot of heat released in the process.

So if you want the reaction to go the other way (which is the same as shifting the equilibrium) you have to add back the heat and then some to get the MgCl2 and H2 to decompose and try to make the products of HCl and Mg metal.

I'll use an easy example, like mixing natural gas (CH4) with air (O2).

Since everyone knows you mix air with natural gas, it burns, it is easy to put reactants on the left and the products on the right. So the natural equilibrium for this reaction is to go to the right:

CH4 + 2O2 ---> CO2 + 2H2O + heat

But if I had CO2 and H2O and heat and I asked you to make CH4 and O2 gas out of it, you would have to add not only the heat it produced from the reaction, but additional heat would be needed to make the CO2 and H2O decompose and form the products of CH4 and O2. This would be shifting the equilibrium to the left. Shifting it to the left would be the same as writing the equation like this:

CO2 + 2H2O + heat --> CH4 + 2O2

So a better description for equilibrium is is just to say which way is the reaction going to happen

alrighty? hope it helps!!!

Answer 3

wow.. that's very fast answer :D

Answer 4

Ypu! i got it from my sister i learned to type rlly fast. u should see how fast my sister is

Answer 5

Mg (s) + 2 HCl (aq) arrow MgCl2 (aq) + H2 (g)
Let's analyze each answer

Increasing the mass of magnesium

M = gr/mr x 1000/ solvent
M = n x solvent in liter

If we increase the mass of magnesium, then its concentration will increase.
The reaction will shifts to the right (forward).

Changing HCl solution from 0.500 moles in 0.5 liters to 0.500 moles in 1.5 liters
It will increase the concentration of the reactant, the reaction will shifts to the right.

Decreasing the pressure of the system

Mg (s) + 2 HCl (aq) arrow MgCl2 (aq) + H2 (g)
reactant reaction coefficient is higher than product reaction coefficient

Once we decrease the pressure of increase the volume, the reaction will shift to the highest reaction coefficient (in this case is the reactant). So in this case, it will shifts to the left

Increasing the surface area of the magnesium solid
If we increase the surface area, then the mass will increase too. That's means the concentration will increase too, so the the reaction will shift to the right.

The answer is point C