## Assessment Tips

There are five topics in Pūtaiao 102

1. Genetics (ext.) – finished in Term 1
2. Microbes (int.) – finished yesterday
3. Chemistry Tūhura (int.) – we were half-way through this topic when the lockdown began in Term 1
4. Mechanics (ext.)
5. Chemical Reactions (int.)

## AS 90930

Chemistry Tūhura

(The 2nd half)

Internal, 4 Credits

For the assessment, you must:

1. Conduct a Chemistry whakamātau (2 periods)
2. Write a report on the whakamātau and the data you have gathered (1 period)

To get an Achieved, you must:

1. Write the method of your whakamātau
2. Identify variables (Independent, Dependent and Control)
3. Make repeat measurements and calculate the average
4. Describe the trend in the results/data
5. Write the conclusion based on the data collected

To get an Merit, you must:

1. Write the method of your whakamātau to a higher quality
2. Identify variables and describe how the control variables have been controlled
3. Make accurate, repeat measurements and calculate the average
4. Describe the trend in the results/data
5. Write the conclusion based on the data collected

To get an Merit, you must:

1. Explain how the control variables that could have significantly affected the results have been controlled
2. Explain the techniques/methods that were used to ensure the accuracy of the results obtained

To get an Excellence, you must:

1. Complete everything up to Merit level, plus:
2. Explain your results using the “Collision Theory”
3. Discuss the techniques/methods you have used to ensure the results you obtained are reliable and valid
4. Discuss on how your method could improve

### Step 1: Aim & Hypothesis

2. Come up with an aim (What are you investigating? Be specific.)
• Get this from your instruction card
3. Come up with a hypothesis (What do you predict? Be specific.)
• I think that the rate of reaction will [increase/decrease] when the [surface area/temperature/concentration] [increases/decreases].

### Step 2: Variables

• Independent Variable: The variable that you will change. What are we changing? Include units, measurement apparatus & range of measurements.
• Dependent Variable: The variable being measured. What are you measuring? Include units & measurement apparatus.

### Step 3: Control Variables & Reliability

• Control Variable: Things that you are keeping constant. What will you not change throughout your whakamātau?
• Reliability: An whakamātau is reliable if the results are within x seconds of each other when the method is repeated. The same method must give the same results each time.

### Step 4: Method

• Give you method as a numbered list,
• List what equipment you will need (e.g. a 100ml beaker; 25ml of diluted $HCl$),
• Break things up into small steps and say when you repeat a set of steps,

### Step 4: Continued

• State your range of measurement for your independent variable, its units and how you will measure it,
• States some control variables and how to control them during the whakamātau.

### Step 5: Data/Results

• Design a table to record your results before you start the whakamātau,
• You will need to think about how many trials you are going to do, how many measurements you will make and calculating an average.

Trial 1Trial 2Trial 3Average
Powder
Small Chips
Large Chips

Average: Add up all your trial times (in seconds) and divide by the number of trials.

### Step 6: Data/Conclusion

• Needs to link to your aim and reflect the data you gathered.
• In our whakamātau we investigated [your-aim-here] and we found that when the [temperature/surface area/concentration] was [increased/decreased] that the reaction went [slower/faster]. This tells us that the rate of reaction [increased/decreased]. This is reflected in our results, for example [two-pieces-of-data-compared-here].

If you have successfully filled out the document as we have discussed, you now have a merit!

This next step is for excellence!

### Step 7: Discussion/Evaluation

• Describe collision theory and how the particles changed between each test of your independent variable. E.g. When the temperature is high… and when the temperature is low..
• Is your data reliable? Talk about the how similar all the data is for each test of your independent variable, were any mistakes made? It’s okay to be honest here.
• Why is the method valid? Why would it produce the same results if tried again today? Talk about control variables and what they are doing to make the whakamātau valid.