OCR Chemistry A – 'How Fast' (5.1.1) Test 2 of 2

TICK ALL THAT APPLY: Which of these represent the Arrhenius equation?

• $rate\ =\ Ae^{\frac{E_A}{RT}}$

• $rate\ =\ Ae^{-\frac{E_A}{RT}}$

• $\ln\left(k\right)\ =\ \ln\left(A\right)\ -\ \frac{E_A}{RT}$

• $k\ =\ Ae^{-\frac{E_A}{RT}}$

If ln(k) is plotted against 1/T, what do the y intercept and gradient represent?

• y intercept = A; gradient = -Ea/R

• y intercept = ln(A); gradient = -Ea/R

• y intercept = ln(A); gradient = Ea/R

• y intercept = -ln(A); gradient = -Ea/R

ln(k) is plotted against 1/T, and the gradient was found to be -18300. What is the activation energy, in kJ mol^-1?

• -152

• -152000

• 152000

• 152

ln(k) is plotted against 1/T, and the gradient was found to be -263. What is the activation energy, in kJ mol^-1?

• 2.19

• 2190

• -2190

• -2.19

TICK ALL THAT APPLY: Why does the rate of reaction increase with temperature?

• There are more collisions

• Particles collide more frequrntly

• A greater proportion of collisions have energy exceeding the activation energy

• The activation energy is lowered

TICK ALL THAT APPLY: Which of these graphs correctly represent how rate constants vary with temperature?

• 
• 
• 
• 

Using this data, what is the rate equation for the reaction:

A + 2B + C --> Products

• rate = [A]²[B][C]

• rate = [A][C]

• rate = [A][B]

• rate = [A]²[C]

The half life of a first order reaction was found to be 37 seconds. What is the value, and what are the units, of the rate constant?

• 0.0541 s^-1

• 0.0187 mol^-1 dm³ s^-1

• 0.0541 mol^-1 dm³ s^-1

• 0.0187 s^-1

TICK ALL THAT APPLY: Which of these explain why the rate of reaction increases as concentration increases?

• There are more collisions

• There are more frequent collisions

• A greater proportion of collisions have energy greater than the activation energy

• The activation energy decreases

In the first order reaction A --> B, the concentration of A was initially 1 mol dm^-3. After 30 s, the concentration of A was 0.5 mol dm^-3. What will the concentration of A be 90 seconds from the start of the reaction?

• 0.25 mol dm^-3

• 0.125 mol dm^-3

• 0.0625 mol dm^-3

• It is not possible to say