1. Salt in Sand Lab- Day 2 Mr. Forte & Ms. Shafai’s Chemistry Classes

2. Step 1: Get your beakers & Weigh beaker 2 ZGet beakers from the tray labeled with your period (make sure it is yours) ZFind mass and record mass in the data table Beaker 2 final mass ___ g Mass of salt (= to Beaker 2 final mass- beaker 2 initial mass) ____ g

3. Step 2: Weigh Beaker 1 ZFind mass and record mass in the data table Beaker 1 final mass ___ g Mass of sand (=Beaker 1 final - Beaker 1 initial- mass of filter paper initial) ____ g

4. Step 3: Observations ZLook at your beakers ZDescribe the contents in each beaker in your lab notebook ZIs there evidence that we have a pure substance in one or both beakers? (Write answers in notebook)

5. Step 4: Calculate how much lighter the sand is now ZLook at Day 1 Sand Mass (line e) and subtract Day 2 Final Sand Mass from it. ZWhy is there a difference in the mass of the sand? Where did the rest of the mass go? (Write answers to these questions in notebook)

6. Step 5: Compare the mass of sand lost to the mass of salt ZCalculate the difference between the amount of sand lost and the final mass of salt (step 4-step1) ZHow close are these two numbers? Where did the difference in mass go?

7. Step 6: Calculate percentage of salt in the original sand sample ZTake your final mass of salt and divide it by our mass of sand determined on day 1 (line e). ZWrite all calculations and label each component in notebook (DON’T FORGET SIGNIFICANT FIGURES!)

8. Step 7: Clean Up ZDispose of filter and sand in trash ZRinse both beakers with tap water (make sure to get salt out) ZReturn empty/washed beakers to tray you got them from

9. Analysis of Data: ZWe must measure the accuracy of our experimental data ZThis measurement is called “percent error” ZThis value is found by comparing our experimental data to a known/given value

10. Read handout about % error ZLook at and take turns reading aloud from handout ZWhat is the purpose of calculating percent error? ZWhy do we use an absolute value when calculating the difference between your result and the expected? (Write answers in your lab notebook)

11. Calculate percent error ZExpected results were 4.00 % salt in sand ZCalculate your percent error and record in your notebook using the following equation: % error= I your result - 4.00% I * 100 4.00%

12. Congratulations- if you got this far, you do not have homework!