R18e(combustion of diamond)

The experiments of combustion of diamond

PURPOSE

This experiment is effective when teaching followings.

[Chemical change]

[Atom and molecule]

[Allotropic modification]

TARGET

Junior high school students (Grade7-9)

CATEGORY

Chemistry

HOW TO MAKE (MATERIALS)

・Diamond(about φ1.5mm)

・Quartz glass round-bottom flask(50mL)

・Plastic bag(80mm × 150mm)

・Drinking straw(φ6mm)

・Gaseous oxygen(5.0L , 95%)

・single hole rubber stopper

・Glass tube(Outer diameter: 6mm, Inner diameter:4mm, length:50mm)

・torch burner(CB-TC-BX)

・Magnesium ribbon

・Drier(SU-13, 1200W)

・plugs and leads

・stand table

・10% hydrochloric acid

・heat-resistant glove

＜Ignition system＞

・single hole rubber stopper

・Glass tube(Outer diameter: 6mm, Inner diameter:4mm, length:50mm)

・Copper wire(φ1mm × 100mm)…3

・Nichrome wire(coil form, 600W, φ0.7mm, 10mm)

・Crimped terminal(DZ-P-2/Z(20), Outer diameter:4.0mm, Inner diameter:2.4mm)…2

・Plastic bag(70mm × 100mm)

HOW TO USE

Combustion of the diamond

- Put a diamond in a flask.

- Oxygen is injected into the flask as shown in Fig.1.

- Attach a rubber plug, which is stabbed a glass tube, onto the flask. Connect a plastic bag (70mm×100mm) into the other side of the tube as shown in Fig 2.

- Hold the mouth of the flask, strongly heat a diamond as shown in Fig.2.

- After about one minute, the diamond reaches red heat.

- After ten several seconds, the diamond starts combustion.

During combustion, the diamond in the flask must be shaken to enhance the contact between the diamond and oxygen.

(The diamond is invisible)

Deoxidize CO2.

- After the diamond burns out and the flask is cooled down, the rubber plug is swiftly exchanged with the tool illustrated in Fig.5.

- The flask is fixed on a stand table. Electric current (10A) is supplied to the heating wire to ignite the magnesium ribbon, as shown in Fig.6.

- The magnesium reacts with the oxygen and carbon dioxide in the flask, as shown in Fig.7.

- After the reaction is over and the flask has cooled down, the products are removed from the flask and put on white paper as shown in Fig.8. Students can easily recognize the black powder (carbon) in it.

By acid dissolve both the magnesium metal and magnesium oxide.

- Put the products into flask.

- 10% hydrochloric acid (about 20 mL) adds into flask and dissolves the remains.

MgO + 2HCl → MgCl2 + H2O

Mg + 2HCl → MgCl2 + H2

- Black powder (carbon) remains in the solution.(cf.fig.9)