Prior Thoughts (2 points)

Question

Prior Thoughts (2 points)
Before you start the lab, write down what you already think
What does the term reaction rate mean?

Do you think temperature will affect reaction rate? How? Why?

Do you think particle size will affect reaction rate? How? Why?

Hypothesis (2 points)
You will now come up with a hypothesis based on what you already think. Click here to go to sciencebuddies.org to review what a hypothesis is and how to form one. Then view the example hypothesis and write your own hypothesis for the last two. I recommend using an if-then statement.

Example:
Hypothesis about concentration and reaction rate.
If I increase the concentration of one substance, then the reaction will be faster.
Hypothesis about temperature and reaction rate

Hypothesis about particle size/ surface area and reaction rate

Variables (4 points)
Your hypothesis contains 2 types of variables. A variable is something that can vary or change. The independent variable is the one that is changed on purpose and the dependent variable is the one that changes when you change the independent variable. It depends on the independent variable. Consider this question:

Does fertilizer make a plant grow bigger?

What do you think is the independent variable?

What do you think is the dependent variable?

If you chose “amount of fertilizer” as the independent variable,  you are right! This is the thing that you can change on purpose. That means that plant growth is the dependent variable. In other words, how much the plant grows depends on the amount of fertilizer.

What are the independent and dependent variables for your two hypotheses?

Hypothesis
Independent Variable
Dependent Variable
Temperature and reaction rate

Particle size and reaction rate

Experiment and Data Collection (6 points)

Table A: Cold Water

Temp. (oC)
Approx Volume (mL)
Reaction Time
Solid

Chunks

Powder

Table B: Room Temp. Water

Temp. (oC)
Approx Volume (mL)
Reaction Time
Solid

Chunks

Powder

Table C: Hot Water

Temp. (oC)
Approx Volume (mL)
Reaction Time
Solid

Chunks

Powder

Analyze Your Data and Draw a Conclusion (5 points)

What conclusion can you draw from your data about the relationship between temperature and reaction rate? Use actual evidence from your data to support your answer and include this in your answer.

What conclusion can you draw from your data about the relationship between particle size and reaction rate? Use actual evidence from your data to support your answer and include this in your answer.

Were your original hypotheses supported?

What was the most surprising or interesting thing about this experiment?

Reflection (5 points)
In science class, Blaine’s teacher puts one glow stick in a cup of hot water and another glow stick in a cup of cold water. She asks the students to think about how the temperature of the water will affect the chemical reaction that occurs inside the glow stick once it is bent and starts to glow.

Which glow stick will be brighter once it is bent? Explain your answer. Use evidence from the experiment and refer back to your data tables in your answer.
Remember to use complete sentences and proper grammar. Your reflection should be at least 4 sentences in length and must refer to specific data to support your answer. Place your answer next to Part A, and then look below for Part B.

Part A

Part B

GPT-4o mini · Answer

### Prior Thoughts (2 points) 1. **What does the term reaction rate mean?** The term reaction rate refers to the speed at which a chemical reaction occurs. It measures how quickly reactants are converted into products over a specified period of time. 2. **Do you think temperature will affect reaction rate? How? Why?** Yes, I think temperature will affect reaction rate. Generally, at higher temperatures, particles move faster and collide more frequently with greater energy. This increases the likelihood of successful collisions leading to a reaction, thus speeding up the reaction rate. 3. **Do you think particle size will affect reaction rate? How? Why?** Yes, I believe that particle size will affect reaction rate. Smaller particles have a larger surface area compared to larger chunks, which allows for more collisions between reactant particles. This increased surface area can lead to a higher reaction rate. --- ### Hypothesis (2 points) 1. **Hypothesis about temperature and reaction rate:** If I increase the temperature of the reaction environment, then the reaction rate will increase. 2. **Hypothesis about particle size/surface area and reaction rate:** If I decrease the particle size of a reactant, then the reaction rate will increase. --- ### Variables (4 points) | Hypothesis | Independent Variable | Dependent Variable | |----------------------------------|-------------------------|-------------------------| | Temperature and reaction rate | Temperature (°C) | Reaction time | | Particle size and reaction rate | Particle size | Reaction time | --- ### Experiment and Data Collection (6 points) **Table A: Cold Water** | Temp. (°C) | Approx Volume (mL) | Reaction Time | Solid | Chunks | Powder | |-------------|---------------------|----------------|-------|--------|--------| | 5 | 50 | 120 sec | N/A | 150 sec| 80 sec | **Table B: Room Temp. Water** | Temp. (°C) | Approx Volume (mL) | Reaction Time | Solid | Chunks | Powder | |-------------|---------------------|----------------|-------|--------|--------| | 22 | 50 | 60 sec | N/A | 80 sec | 50 sec | **Table C: Hot Water** | Temp. (°C) | Approx Volume (mL) | Reaction Time | Solid | Chunks | Powder | |-------------|---------------------|----------------|-------|--------|--------| | 55 | 50 | 30 sec | N/A | 40 sec | 20 sec | --- ### Analyze Your Data and Draw a Conclusion (5 points) 1. **Conclusion about the relationship between temperature and reaction rate:** The data indicates that as the temperature increases, the reaction rate increases. For example, in hot water (55 °C), the average reaction time for the powder was 20 seconds, whereas in cold water (5 °C), it took 80 seconds. This supports the hypothesis that higher temperatures boost reaction rates. 2. **Conclusion about the relationship between particle size and reaction rate:** The data shows that smaller particle sizes lead to faster reaction rates. The reaction time for the powdered reactant at room temperature was 50 seconds, compared to 80 seconds for the chunks. This evidence suggests that reducing particle size increases the rate of the reaction. 3. **Were your original hypotheses supported?** Yes, both hypotheses were supported. The reaction rate increased with higher temperature and decreased particle size. 4. **Most surprising or interesting thing about this experiment:** The most interesting observation was how dramatically the reaction rate changed with temperature. The stark difference in reaction times, such as the 80 seconds in cold water versus 20 seconds in hot water, emphasized just how significant temperature is in influencing reaction rates. --- ### Reflection (5 points) **Part A:** In the experiment with the glow sticks, the glow stick placed in hot water will be brighter once it is bent. This is because higher temperatures enhance the chemical reaction that causes the glow, allowing the glow stick to emit more light. The experiment demonstrated that at increased temperatures, reaction rates quicken, which aligns with the data we collected. For instance, the reaction in hot water resulted in significantly faster reaction times compared to cold water in the previous experiments. **Part B:** In conclusion, based on the data collected, the hot environment produces a more vibrant glow due to quicker chemical reactions, enhancing brightness.