Conservation of Matter

= = Conservation of Mass Lab<= /o:p>

Matter cannot be created or destroyed by a chemi= cal change. This very important principle is known as the Law of Conservation of Matter. This law applies to ordinary chemi= cal reactions (as opposed to nuclear reactions, where matter may be changed to energy). During a chemical ch= ange (reaction), the atoms of one or more substances (reactants) simply undergo = some “rearrangements.” The result of these rearrangements is the formation of a new, different substance (products). All of the original atoms are still present. It is because of the= Law of Conservation of Mass that we are able to write balanced chemical equatio= ns. Such equations make it possible to predict the masses of reactants and products that will be involved in a chemical reaction.

Sulfur reacts with metals such as iron. A gas es= capes, and the metal seems to disappear. What happens to the atoms of the metals in these reactions? Are they destroyed? If not, where do they go?

PROBLEM (can be changed to form hypothesis)

What happens to the atoms of sulfur and iron fil= ing when they react?

Fe + S à FeS=

OBJECTIVES

• Infer what happens to atoms during a chemical change.

• Compare experimental results to the law of conservation of matter.

MATERIALS

Balance

Iron filing

Powdered sulfur

Striker

Bunsen burner

Test tube

Test tube holder

Test tube rack

SAFETY PRECAUTIONS

Use care when handling hot objects. Wear goggles= and laboratory aprons. Perform this ChemLab in a well-ventilated room.

PROCEDURE

1. Weigh a clean, dry, glass test tube to the neare= st 0.01 g. Record its mass in the data table.

2. Obtain a sample of sulfur, and add it to your te= st tube. Weigh the test tube with the sulfur in it. Record the total mass in t= he data table. Subtract to find the mass of sulfur. The mass of sulfur must be between 03.40 g and 03.60 g. If you have too much sulfur, remove some with a clean spoon or spatula until the mass is in the range described.

3. Add 6.00 g of iron filings to the test tube. Sti= r and mix the contents and look for signs of a chemical change. Record your observations in the data table.

4. Heat= the test tube strongly with the Bunsen burner. Again look for signs that a chemical change is taking place, and record your observations in the data table.

5. Once t= he reaction is complete, allow the test tube and its contents to cool. W= eigh test tube with the new product to the nearest 0.01 g. Record its mass in the data table.

6. CAUTION: Be careful not to inhale the fumes from the test= tube.

DATA AND OBSERVATIONS

Mass of test tube
Mass of test tube and sulfur
Mass of sulfur
Mass of test tube with sulfur and iron
Mass of iron
Mass of reactants
Mass of products
What did you see when the sulfur and iron were mixed=
What did you see when the iron and sulfur was heated= .
What evidence proved that a chemical reaction occurr= ed?

ANALYZE AND CONCLUDE

1. Interpreting Data How did the mass of the product, iron sulfide, compare with the mas= s of the iron and sulfur?

2. Interpreting Observations How can you account for the difference in mass?<= /span>

3. Observing and Inferring What happened to the iron and sulfur?

4. Making Inferences Why were the test tube and its contents heated?

APPLY AND ASSESS

1. Was a mixture formed during this lab? Explain

2. Did a chemical reaction occur? Explain

3. How does this experiment support the law of conservation of matter?

4. How could you modify the procedure so that the l= aw of conservation of matter is better demonstrated?

= Conservation of Mass Lab

Matter cannot be creat= ed or destroyed by a chemical change. This very important principle is known as the Law of Conservation of Matter. This law applies to ordinary chemical reactions (as opposed to nuclear reactions, where matter = may be changed to energy). During= a chemical change (reaction), the atoms of one or more substances (reactants) simply undergo some “rearrangements.” The result of these rearrangements is the formation of a new, different substance (products). All of the original atoms are stil= l present. It is because of the Law of Conser= vation of Mass that we are able to write balanced chemical equations. Such equations make it possible to predict the masses of reactants and products that will be involved in a chemical reaction.

Sulfur reacts with met= als such as iron. A gas escapes, and the metal seems to disappear. What happens= to the atoms of the metals in these reactions? Are they destroyed? If not, whe= re do they go?

PROBLEM (can be changed to form hypothesis)

What happens to the at= oms of sulfur and iron filing when they react?

Fe= + <= /span>S à FeS

OBJECTIVES

• Infer <= /b>what happens to atoms = during a chemical change.

• Compare experimental results t= o the law of conservation of matter.

MATERIALS

Balance

Iron filing=

Powdered sulfur

Striker

Bunsen burner

Test tube

Test tube holder<= /o:p>

Test tube rack

SAFETY PRECAUTIONS

Use care when handling= hot objects. Wear goggles and laboratory aprons. Perform this ChemLab in a well-ventilated room.

PROCEDURE

1. Weigh= a clean, dry, glass test tube to the nearest 0.01 g. Record its mass in the d= ata table.

2. Obtai= n a sample of sulfur, and add it to your test tube. Weigh the test tube with the sulfur in it. Record the total mass in the data table. Subtract to find the mass of sulfur. The mass of sulfur must be between 03.40 g and 03.60 g. If = you have too much sulfur, remove some with a clean spoon or spatula until the m= ass is in the range described.

3. Add 6= .00 g of iron filings to the test tube. Stir and mix the contents and look for si= gns of a chemical change. Record your observations in the data table.

4. Heat the test tube strongly with the Bunsen burner. A= gain look for signs that a chemical change is taking place, and record your observations in the data table.

5. Once the reaction is complete, allow the test tube and its contents to cool. Weigh test tube with the new produ= ct to the nearest 0.01 g. Record its mass in the data table.

6. CA= UTION: Be careful not to inhale the fumes from the test tube.

DATA AND OBSERVATIONS

Mass of test tube

Mass of test tube and sulfur=

Mass of sulfur

Mass of test tube with sulfur and iron

Mass of iron

Mass of reactants

Mass of products

What did you see when the sulfur and iron were= mixed

What did you see when the iron and sulfur was heated.

What evidence proved that a chemical reaction occurred?

ANALYZE AND CONCLUDE

1. Interpreting Data How did the mass of the product, iron sulfide, compare with the mas= s of the iron and sulfur?

2. Interpreting Observations How can you account for the difference in mass?<= /span>

3. Observing and Inferring What happened to the iron and sulfur?

4. Making Inferences Why were the test tube and its contents heated?

APPLY AND ASSESS

1. Was a mixture formed during this lab? Explain

2. Did a chemical reaction occur? Explain

3. How does this experiment support the law of conservation of matter?

4. How could you modify the procedure so that the l= aw of conservation of matter is better demonstrated?

Mass of test tube
Mass of test tube and sulfur=
Mass of sulfur
Mass of test tube with sulfur and iron
Mass of iron
Mass of reactants
Mass of products
What did you see when the sulfur and iron were= mixed
What did you see when the iron and sulfur was heated.
What evidence proved that a chemical reaction occurred?