Rate Calcs/Graphs
6 seconds (where they cross)
Blue (It's a reactant, so concentration goes down)
Why does a higher temperature lead to a higher reaction rate?
Higher temp = More energy = Faster particles = More collisions and more energetic collision
For the reaction 2A + 3B → 4C + 5D,
If 3 moles of B react, how many moles of D are made?
5
2 HCl(aq) + Na2S2O3(aq) → S(s) + H2SO3(aq) + 2 NaCl(aq)
Increasing the concentration of Na2S2O3(aq) increases the rate of reaction because...
Higher concentration = More collisions = More collisions happening with the "correct angle"
-0.231 M/s
Steeper curve (faster reaction)
Pressure impacts the rate of reactions for which type of substance/state of matter?
Gas
For the reaction 2A + 3B → 4C + 5D,
If the rate of change for A is -1.5 M/s, what is the rate of production for C?
C is two times bigger, so it happens two times faster
Why can an increase in temperature lead to more "effective collisions" between reactant particles and an increase in the rate of a chemical reaction?
Higher temperature = More energy = More particles that have "enough energy" to react
** Over the activation energy
If the initial concentration of N2 was 0.500 M and the concentration of N2 was 0.450 M after 0.100 s, what is its average rate of depletion?
.500-.450 --> 0.05 M
DIVIDED BY 0.100 s
0.5 M/s
Shallower - Lower temperature
Why does a lower concentration of reactants lead to a slower reaction rate?
Lower concentration = Fewer reactant particles = Fewer collisions
For the reaction 2A + 3B → 4C + 5D,
If D is made at a rate of +0.085 M/s, what is the rate of depletion for B?
- 0.051 M/s
** 0.085 / 5 *3
Black --> Going down most quickly
Steeper - Higher concentration
Why does a powder react more quickly than a chunk of the substance? (Assuming they have the same mass)
The powder has more spaces that can be hit by the other reactants (higher surface area). Allowing more collisions to take place.
2HI(g) → H2(g) + I2(g)
If the concentration of HI changes at a rate of –0.45 M/s, what is the rate of appearance of I2(g)?
0.45 M/s / 2 * 1 --> +0.225 M/s
At 20°C, a 1.2-gram sample of Mg ribbon reacts rapidly with 10.0 mL of 1.0 M HCl(aq). Which change in conditions would cause the reaction to proceed more slowly? AND WHY
A. Increasing the initial temperature to 25°C.
B. Decreasing the concentration of HCl to 0.1 M.
C. Using 1.2 g of powdered Mg.
D. Using 2.4 g of Mg ribbon.
B - Decreasing concentration (fewer reactant particles, fewer opportunities to react)
B --> Going down, most shallow
NO CHANGE --> Only a factor if reactants are gases
Concentration/amount of reactant decreases/gets used up. Fewer reactant particles means fewer collisions.
If the rate of formation of ammonia (NH3) is 0.345 M/s, what is the rate of disappearance of H2?
N2(g) + 3H2(g) → 2NH3(g)
0.345/2*3 --> -0.5175 M/s
Zn(s) + 2 HCl(aq) → H2(g) + ZnCl2(aq)
Which set of reaction conditions would produce H2(g) at the fastest rate? Why?
A. 1.0 g lump of Zn(s) in 50 mL of 0.5 M HCl(aq) at 20˚C.
B. 1.0 g lump of Zn(s) in 50 mL of 0.5 M HCl(aq) at 30˚C.
C. 1.0 g of powdered Zn(s) in 50 mL of 1.0 M HCl(aq) at 20˚C.
D. 1.0 g of powdered Zn(s) in 50 mL of 1.0 M HCl(aq) at 30˚C.
D -- Highest surface area (powder) and highest concentration (1.0 M) and highest temperature (30˚C)