16. When a reaction is at equilibrium

Chemistry

1 answer:

Ronch [10]2 years ago

8 0

Answer:

The forward reaction rate is equal to the reverse reaction rate

Explanation:

In many cases, a lot of people might think that equilibrium is a state when a reaction stops. This is not the case, however. Notice that equilibrium reactions are represented by double arrows indicating that two reactions take place simultaneously: both a forward and a reverse reaction.

When equilibrium is reached, the rate of a forward reaction becomes equal to the rate of a reverse reaction. The two reactions don't stop and still take place, just at equal rates. This is the reason why the concentrations of reactants and products are kept constant at equilibrium: the rates of the two reactions are balanced.

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In a reaction 4 NH3 + 5 O2 → 4 NO + 6 H2O, 1 mole of ammonia reacts with 2 moles of oxygen. Which of these is correct after the

Vsevolod [243]

Answer:

Option B) All the ammonia is consumed

Explanation:

1. Balanced chemical equation (given):

$4NH_3+5O_2\rightarrow 4NO+6H_2O$

2. Theoretical mole ratios:

$4molNH_3:5molO_2:4molNO:6H_2O$

3. Limiting reactant:

When 1 mole of ammonia is combined with 2 moles of oxygen, the mole ratio is:

$1molNH_3:2molO_2$

Hence, one of the reactants will be completely consumed (the limiting reactant) and, after completion, an excess of the other will remain unreacted.

You need to compare the the actual ratio with the theoretical ratio.

4/5 > 1/2

Hence, NH₃ is in less proportion with respect to oxygen than what is theoretically needed, and the former is the limiting reactant.

Therefore, the 1 mole (all) of ammonia will be consumed, while some oxygen will remain as excess. This is described by the option B) All the ammonia is consumed.

4. Analyze the other options:

The amount of oxygen that will react is:

$1molNH_3\times5molO_2/4molNH3=5/4molO_2$