What makes reactions go faster

Answer Key - Grade 10 Science Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   At 10 s a reaction has made 24 mL of gas, and at 20 s it has made 40 mL. What is the average rate between those times, Ari?

   1.6 mL/s
2. 2.

   At 20 s a reaction has made 40 mL of gas, and at 30 s it has made 50 mL. What is the average rate between those times, Bo?

   1 mL/s
3. 3.

   At 10 s a reaction has made 24 mL of gas, and at 30 s it has made 50 mL. What is the average rate between those times, Esme?

   1.3 mL/s
4. 4.

   Which change speeds up a reaction, Jun?

   • Raising the concentration
   • Lowering the temperature
   • Using one large lump instead of powder
5. 5.

   A catalyst lowers the activation energy. What does it do to ΔH, Luz?

   • It flips ΔH's sign
   • It makes ΔH twice as big as before
   • Nothing: ΔH stays the same
6. 6.

   Why don't all collisions between reactant particles cause a reaction, Milo?

   • Light particles are unable to react
   • Some lack energy or the right angle
   • Particles bounce apart before touching
7. 7.

   Why doesn't a log burn on its own at room temperature, Pia?

   • Burning is endothermic
   • Wood can't react with oxygen
   • Too few collisions have enough energy
8. 8.

   Reaction A makes 30 mL of gas in 10 s; reaction B makes 30 mL in 20 s. Which is faster, Ren?

   • Reaction B
   • They are equal
   • Reaction A
9. 9.

   A rate is found from milliliters of gas and seconds. What are its units, Tala?

   • mL/s
   • s/mL
   • mL × s
10. 10.

    The same reaction runs at 20 °C and at 40 °C. Which run's curve rises more steeply, Zee?

    • The 40 °C run
    • They rise the same
    • The 20 °C run