When a system at chemical equilibrium is subjected to an external stress — such as a change in concentration, pressure, or temperature — the equilibrium shifts in the direction that relieves the stress.
Push on equilibrium, and it pushes back. Add something, and the system uses it up.
Showing a random 20 of 50 problems.
Example 1
medium
For AgCl(s)⇌Ag+(aq)+Cl−(aq), adding NaCl(aq) has what effect on the solubility of AgCl?
Example 2
easy
For an exothermic reaction at equilibrium, does cooling shift it toward reactants or products?
Example 3
medium
Why does changing concentration shift the equilibrium position but NOT change K, while changing temperature changes K?
Example 4
medium
For CO2(g)+H2O(l)⇌H2CO3(aq), opening a carbonated drink bottle causes what shift?
Example 5
medium
For 2SO2(g)+O2(g)⇌2SO3(g), ΔH<0. Predict the shift for: (a) adding O2, (b) raising T, (c) raising P, (d) removing SO3.
Example 6
medium
For A(g)⇌2B(g), the number of gas moles increases left to right. Does decreasing pressure favor reactant or product?
Example 7
easy
Le Chatelier's principle: if you add more reactant to a system at equilibrium, which way does it shift?
Example 8
medium
For N2O4(g)⇌2NO2(g), ΔH>0. When the temperature is raised, what happens to (a) Kc and (b) the equilibrium [NO2]?
Example 9
easy
If you remove a product from a system at equilibrium, which way does it shift?
Example 10
medium
At constant volume, an inert gas (e.g., Ar) is added to N2(g)+3H2(g)⇌2NH3(g). Predict the shift.
Example 11
medium
For the equilibrium CaCO3(s)⇌CaO(s)+CO2(g) (endothermic), predict the effect of increasing temperature on the amount of CO2 produced.Increasing temperature shifts this endothermic equilibrium right, producing more CO₂
Example 12
medium
For CaCO3(s)⇌CaO(s)+CO2(g), predict the effect of (a) removing CO2, (b) adding more CaCO3.
Example 13
easy
Adding an inert gas at constant volume changes the total pressure. Does it shift the equilibrium position?
Example 14
medium
In the Haber process N2+3H2⇌2NH3 (exothermic), why is a compromise moderate temperature used instead of low temperature?
Example 15
medium
For 2NO(g)+O2(g)⇌2NO2(g), ΔH<0. Predict the effect on yield of: (a) raising T, (b) increasing P, (c) removing NO2.
Example 16
easy
For N2+3H2⇌2NH3, increasing pressure favors which side?Increasing pressure shifts equilibrium toward NH₃ (fewer moles of gas on product side)
Example 17
medium
For the exothermic reaction N2+3H2⇌2NH3+heat, predict the effect of: (a) increasing temperature, (b) removing NH3, (c) increasing pressure.
Example 18
challenge
For exothermic N2+3H2⇌2NH3, you simultaneously raise temperature and pressure. Predict the competing effects on NH3 yield.
Example 19
medium
In 2NO2⇌N2O4, the system is compressed (volume halved). Predict the shift and explain.Compressing the container (volume halved) shifts equilibrium toward N₂O₄ (2 mol → 1 mol gas)
Example 20
easy
Does adding a catalyst shift the equilibrium position?