Lab #3 Comparing the density of Metals



Name: __________________________________ Date: _________________ P___R___S___ Prelab Due: _______

Lab Partner: ______________________________________________ Lab Due: _________

Honors Chemistry / CPA Chemistry

Density Lab – Metal Identification

Prelab questions:

1. Draw the triangle for Density Formula

2. Can I write density of metal g/cm3 as g/mL IF I USE WATER DISPLACEMENT METHOD? ________

Why or Why not? ______________________________________________________________________

3. A sample X has 85.6 g and 12.1 ml.

a) What is the density of sample X? (SHOW ALL FORMULA AND MATH)

b) What is its state of matter? ___________ How do you know? __________________________________

4. A sample Y has 19.3 g/cm3 and 50.0 g.

a) What is the volume of sample Y? (SHOW ALL FORMULA AND MATH)

b) What is its state of matter? ___________ How do you know? __________________________________

5. A sample Z has 25.3 L and 1.42 g/L.

c) What is the mass of sample Z? (SHOW ALL FORMULA AND MATH)

d) What is its state of matter? ___________ How do you know? __________________________________

6. Read the material and procedure and answer the answers:

a) How do you know which metal sample you start with? _______________________________________

b) Before using balance, what do you need to do? ______________________

c) You need to record the mass to the nearest _________, and the volume to the nearest _________.

d) How much water you need to fill in the graduated cylinder? ___________

e) What is the size of the graduated cylinder you will use? _________________

f) After the lab is done, what will you need to do with the metal sample? __________ and ___________

g) Where will you dump the water? __________________

h) What do you need to do with the glassware? __________________.

i) Where do you keep the lab equipment when you are done? __________________

Problem:

Can you identify unknown metals by calculating their density?

Materials (per group):

|4 metals samples A – D (ON TEACHER’S DESK) |100- ml graduated cylinder |Paper towels |250-mL Erlenmeyer Flask |

|Triple Beam Balance |Water (from the sink) |Goggles | |

Procedure:

1. Teacher will assign the metal sample for you. Start with METAL ____________

2. Zero the balance. Use the balance to measure the mass of each sample to the nearest 0.1g. Record the masses.

3. Fill the graduated cylinder half full of water. Record the volume to the nearest 0.1 mL.

4. Carefully insert the metal sample without splashing any water. Record the volume of the water + metal sample to the nearest 0.1 Ml.

5. Repeat for each of the metal samples.

After the lab is completely done, cleanup and disposal:

1. Dry the metal samples. Return the metal IMMEDIATELY back to teacher’s desk once finishing one metal.

2. Dump the water in the graduated cylinder to the sink. Dry the outside. Keep everything on your bench.

Data and Observations

|Data Table (SHOW ALL YOUR MATH) |

|Metal |Mass |Volume of water |Volume of water + metal |Volume of metal sample |Density of metal sample (g/mL) = |Metal Sample |

|Sample |(g) |(mL) |sample (mL) |(mL) |(g/cm3) |Identification |

|Formula |M |V1 |V2 |V2 – V1 = V |M / V = D | |

|A | | | | | | |

|B | | | | | | |

|C | | | | | | |

|D | | | | | | |

|Density of Metal |Density (g/cm3) |Density of Metal |Density (g/cm3) |

|Aluminum |2.699 |Magnesium |1.738 |

|Copper |8.89 |Mercury |13.596 |

|Gold |19.33 |Tin |5.77 |

|Lead |11.347 |Zinc |7.19 |

Post Lab questions:

1. What is the relationship between g/cm3 and g/mL?

2. If there were bubbles in the graduated cylinder would this affect your results? Why or why not?

3. List 2 possible sources of error for this lab.

1)

2)

A B C D

Correct identification

A = Zn B = Pb

C = Cu D = Sn

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