Explain, in terms of particles, concentration, and reaction rate, what you expect to happen when methane gas (CH4) and hydrogen sulfide gas (H2S) are sealed in a flask and reach a state of equilibrium.
CH4 (g) +2 H2S (g)<=> CS2 (g) + 4 H2 (g)
I would look at dGo tables in your text, calculate dGo for the reaction, use that to solve for Keq, then explain how the system reacts.
On a much less work scale, the rate at which CH4 and H2S react decreases with time while the rate at which CS2 and H2 react increases with time. There is a point at which the forward reaction and the reverse direction are equal and this is equilibrium. This should serve to get you started.
When methane gas (CH4) and hydrogen sulfide gas (H2S) are sealed in a flask and allowed to reach a state of equilibrium, several factors related to particles, concentration, and reaction rate come into play.
First, let's talk about the particles involved in the reaction. Methane (CH4) and hydrogen sulfide (H2S) are both gases, and when the reaction takes place, they collide and interact with each other. These collisions between the particles are crucial for the reaction to occur.
Next, the concentration of the reactants and products in the flask also plays a significant role. Concentration refers to the amount of a substance in a given volume. Initially, when the reactants are sealed in the flask, their concentrations are relatively high because there are no significant amounts of products. As the reaction proceeds, the concentration of the reactants decreases, while the concentration of the products increases until equilibrium is reached.
Equilibrium is a state where the forward and reverse reactions occur at the same rate. In this particular reaction, the forward reaction combines methane and hydrogen sulfide to form carbon disulfide (CS2) and hydrogen (H2). Meanwhile, the reverse reaction breaks down carbon disulfide and hydrogen into methane and hydrogen sulfide. At equilibrium, the rates of the forward and reverse reactions are equal.
The reaction rate refers to how quickly the reaction proceeds. Initially, the reaction rate is high because the concentration of the reactants is high, and many collisions occur between the particles. However, as the reaction progresses and the concentrations change, the reaction rate gradually decreases. Eventually, at equilibrium, the reaction rate becomes constant and equal for both the forward and reverse reactions.
It is important to note that equilibrium does not mean that the reactants are completely consumed or that the reaction has stopped. Instead, it signifies that the forward and reverse reactions are happening at the same rate, resulting in a steady state where the concentrations of all the species remain constant.
To determine what will happen at equilibrium, you can use the principles of Le Chatelier's principle. In this reaction, if you increase the concentration of methane or hydrogen sulfide, the reaction will shift to the right (forward direction) to relieve the stress and produce more carbon disulfide and hydrogen. Conversely, if you increase the concentration of carbon disulfide or hydrogen, the reaction will shift to the left (reverse direction) to reduce the stress and produce more methane and hydrogen sulfide.
In summary, when methane gas and hydrogen sulfide gas are sealed in a flask and reach equilibrium, the concentration of the reactants will decrease, while the concentration of the products will increase. The reaction rate will initially be high but gradually decrease until it reaches a steady state at equilibrium. The concentrations of all the species will remain constant, and any changes in concentration will cause the reaction to shift accordingly to reestablish equilibrium.