Lab 17

AP Lab Activity – Growing Crystals

Unit 8⏱ 90 minGuided Inquiry

Overview

How do metal crystals grow from a seeded solution?

Objectives

How do metal crystals grow from a seeded solution?
Connect observations to AP Chemistry models and calculations.

⚠️ Wear protective goggles and an apron. Follow your teacher’s safety directions for all chemicals and equipment.

Materials Needed

Saturated sodium metasilicate – Flinn Scientific (CAT No. S0102) – needs to be diluted to a density of 1.06 g/,L. About 158 mL of the commercial solution diluted to one liter white vinegar Stir rod mL beakers nails graduated cylinders (100 mL and 10 mL) scoopula 0 M Pb(NO3)2 (33.1 g/100 mL water) balance a class set of 20-mL vials tweezers Wear protective glasses at all times. Wash hands before leaving the lab area Do not open the vial after the lab is complete. Remember that heavy metals are a poison and must NEVER be ingested. If you bring it home keep it away from small children

Procedure

Each student will make a crystal growing reaction. Make sure you write your name on the cover of the vial so you can identify which vial is yours. Do not write your name on the side of the vial or you will block your view of the crystal growth. **Each table will make the following solutions and then separate them into your own personal vials to take home.

Measure out 4.0 mL of 1M lead nitrate solution and 52.0 mL of 1M acetic acid into a 250 mL beaker.

Add 56.0 mL of the 1.06 g/mL sodium silicate solution to the beaker. Stir well.

Pour these mixtures into 4 different vials (one per student). Fill to the top and cap. Let the gel harden. (It should take about 4 hours). ---NEXT DAY

Carefully place a nail STRAIGHT into the gel without cracking the gel.

Add some distilled water to the top of the gel.

Cap the vial and let the vial sit overnight. Take it home.

After a few days, you may, CAREFULLY, remove the nail with a pair of tweezers; then recap the vial.

NEVER OPEN THE VIAL AGAIN!!! Crystal Growing Reaction – Lead Crystals Pb+2 (aq) + Zn (s)  Pb (s) + Zn+2 (aq) This lab will not require a formal report. Instead, you will fill out the student activity form associated with this lab activity. PAGE PAGE 70

Pre-Lab Questions