Conservation of Matter – Chemical Change Lab Purpose: Name ______________________ Period _____ 1. I am able to identify an open or closed system by analyzing the inputs and outputs of matter and energy. 2. I can describe how matter is conserved in both an open and closed system. Background: Conservation of Matter (Mass): One of the fundamental laws of nature is conservation of matter. The law states that matter cannot be created nor destroyed during a chemical reaction. • This means all the atoms present before a reaction must be present after the reaction. • Also that these atoms may make up different molecules and change their state of matter. Introduction: In this activity, you will investigate this law by conducting chemical reactions in both open and closed systems. • A closed system is a system in which energy can flow into and out of the system, but matter stays in the system. • An open system is one in which both energy and matter can flow into and out of the system into the environment. Closed systems are very hard to create, so carefully follow instructions during this lab. Materials For each group of 4 students Long pants Closed toed shoes w/socks 1 pair of safety goggles Aprons for all. 1 bottle of 3M Hydrochloric Acid (HCl) 1 scoop 1 electronic balance 1 bottle of Sodium Bicarbonate (NaHCO3) 1 funnel Secondary containment Gloves for the operator Hazards and Safety • Acid and Pressurized gas: You will be using acid in this lab as well as pressurized containers. Use the utmost care not to get acid on you or your teammates. Also open the pressured containers SLOWLY to let the gas out safely. • Wear safety goggles and aprons at all times. Operators are to wear gloves. Do not allow solutions to touch your skin or clothing. Clean up any spills immediately. If accidental contact occurs, rinse exposed areas and inform your teacher as soon as possible. Conservation of Matter – Chemical Change Lab Name ______________________ Period _____ Procedure Part A: Open System Trial Instructions: 1. Create an Open Systems Hypothesis on the worksheet before proceeding. 2. Use a funnel to place 1 level scoop of sodium bicarbonate into your reaction bottle. Be sure to get as much of the powder as possible on the bottom of the reaction bottle instead of the sides. 3. Fill the bottle’s eye dropper lid with 1-­‐mL of 3M hydrochloric acid (HCl). 4. Gently place the filled dropper into the bottle and DO NOT tighten the dropper on the bottle. Do not squeeze the dropper. This will drip hydrochloric acid onto the sodium bicarbonate. 5. Carefully measure the combined mass of the bottle, dropper, and contents to the nearest 0.01g. Record this as the “Start Mass” in the Trial 1 section of Data Table: Open System. 6. Set the bottle in the containment tray and squeeze the dropper to add the entire 1 mL of hydrochloric acid to the sodium bicarbonate. Record your observations in Table 1. If needed, swirl the bottle to mix the reactants until the reaction has finished 7. Measure the final mass of the bottle, dropper, and contents to the nearest 0.01 g. Record this as “Final Mass” in Data Table 1. 8. Calculate the change in mass using the equation below and record this in Data Table 1. Change in Mass = Final Mass – Initial Mass Record to the nearest 0.1 g 9. Rinse out your reaction bottle and dropper with plenty of water. Shake out as much water as possible and dry off the outside of the bottle. Squirt all water out of the dropper. 10. Repeat Steps 1-­‐10. Record your second trial’s data in the Trial 2 part of Data Table 1. Remember: Calculate the Change in Mass to the nearest 0.1 g STOP! Get your lab’s data checked by instructor before moving on answering the questions and analyzing and diagramming the Closed system. Conservation of Matter – Chemical Change Lab Name ______________________ Period _____ Procedure Part B: Closed System Trial Instructions 1. Create a Closed Systems Hypothesis on the worksheet before proceeding. 2. Use a funnel to place 1 level scoop of sodium bicarbonate into your reaction bottle. Be sure to get as much of the powder as possible on the bottom of the reaction bottle instead of the sides. 3. Fill the bottle’s eye dropper lid with 1-­‐mL of 3M hydrochloric acid (HCl). 4. Gently place the filled dropper into the bottle and carefully tighten down the cap firmly. Do not squeeze the dropper and drip HCl onto the NaHCO3. 5. Carefully measure the combined mass of the bottle, dropper, and contents to the nearest 0.01g. Record this as “Start Mass” in the Trial 1 section of Data Table 2: Closed System 6. Set the bottle in the containment tray. Now squeeze the dropper to add the entire 1 mL of HCl to the NaHCO3. Record your observations in Data Table 2. If needed, swirl the bottle to mix the reactants until the reaction has gone to completion 7. Measure the final mass of the bottle, dropper, and contents to the nearest 0.01 g. Record this as “Final Mass” in Data Table 1. 8. Calculate the change in mass. Round to the nearest 0.1g and record this in Data Table 2. Change in Mass = Final Mass – Initial Mass Record to the nearest 0.1 g 9. Very slowly open the reaction bottle and release the gas in the bottle. 10. Rinse out your reaction bottle and dropper with plenty of water. Shake out as much water as possible and dry off the outside of the bottle. Squirt all water out of the dropper. 11. Repeat Steps 1-­‐10. Record the second trial’s data in the Trial 2 part of Data Table 2. Remember: Calculate the Change in Mass to the nearest 0.1 g STOP! Get your lab’s data checked by instructor before moving on answering the questions and analyzing and diagramming the Closed system. Conservation of Matter – Chemical Change Lab Name ______________________ Period _____ Part A: Open System Experimental Trial (30pts for this section) Open System Hypothesis: (4pt) If Then Because Therefore Data Table 1 Open System (8 pts) Observations Start 1. Color Change? 4. Chemical Reaction? Trial Mass to 2. Gas production? 5. Other – Bulb Pressure etc. 0.01 (g) 3. Temperature change? 1 2 1. 2. Final Change in Mass to Mass 0.01 (g) to 0.1(g) 3. 4. 5. 1. Look at the calculated Change in mass in Data Table I above. a. (2pt) Did the actual mass increase / decrease / or stay the same to the nearest 0.1g? (circle one) b. (4pts) Explain why this happened. Be sure to include why this data follows the Law of Conservation of Matter to explain why the mass increased, decreased or remained the same. Conservation of Matter – Chemical Change Lab Name ______________________ Period _____ c. (12pt) Draw a standard SYSTEMS figure of the OPEN system once the Hydrochloric Acid is squirted in the bottle • The diagram should completely show what occurs at this point • Include proper labels to help show or explain your ideas. (Use the key for colors on matter and energy flows/cycles etc.) • Be sure to show o Inputs & flows of matter and energy, o Outputs & flows of matter and energy o and the Systems boundary. Key Green = Matter input Blue = Matter output Purple = Matter cycling Red = Energy Input Orange = Energy Output Boundaries Yellow dashed = Open Yellow solid = Closed Flow: Use Matter and Energy arrows to show the direction of flow Conservation of Matter – Chemical Change Lab Name ______________________ Period _____ Part B: Closed System Experimental Trial (30pts in this section) Open System Hypothesis: (4pt) 68 pts Lab for Total If Then Because Therefore Data Table 2 Part II: Closed System (8pts) Observations Start 1. Color Change? 4. Final color Trial Mass to 2. Gas production? 5. Other – Bulb Pressure etc. 0.01(g) 3. Temperature change? 1 1. 2. Final Mass to 0.01 (g) Change in Mass to 0.1(g) 3. 2 4. 5. 1. Look at the calculated change in mass in Data Table 2 above. a. (2pts) Did the actual mass increase / decrease / or stay the same? [to the nearest 0.1g] (circle one) b. (4pts) Explain why this happened. Be sure to include why this data follows the Law of Conservation of Matter to explain why the mass increased, decreased or remained the same. Conservation of Matter – Chemical Change Lab Name ______________________ Period _____ c. (12pt) Draw a standard SYSTEMS figure of the Closed system once the Hydrochloric Acid is squirted in the bottle • The diagram should completely show what occurs at this point • Include proper labels to help show or explain your ideas. (Use the key for colors on matter and energy flows/cycles etc.) • Be sure to show o Inputs & flows of matter and energy, o Outputs & flows of matter and energy o and the Systems boundary. Key Green = Matter input Blue = Matter output Purple = Matter cycling Red = Energy Input Orange = Energy Output Boundaries Yellow dashed = Open Yellow solid = Closed Flow: Use arrows to show the direction of Matter & Energy flow Conservation of Matter – Chemical Change Lab Name ______________________ Period _____ Part C – Final Analysis and Conclusion 1. (8 pts) Explain how this experiment demonstrated the Law of Conservation of Matter. In your explanation, be sure to: a. Use data from both Part A Open Systems and Part B Closed system trials above b. Include why this data follows the law of Conservation of Matter.