technopolt.blogg.se - Atomic mass of magnesium chloride

#ATOMIC MASS OF MAGNESIUM CHLORIDE FREE#

Weigh accurately, to the nearest 0.001 g, a length of magnesium ribbon, approximately 3–4 cm long.Do NOT leave in a place where pupils would have potentially unsupervised access. Cut the ribbon into lengths of 3–4 cm (which will yield around 30 cm 3 of hydrogen when reacted). Clean the magnesium ribbon with emery paper to remove the grey oxide layer, so that it appears shiny and metallic. Magnesium ribbon, Mg(s) – see CLEAPSS Hazcard HC059A.Provide the hydrochloric acid in small bottles or corked conical flasks, labelled, suitable for pouring the acid into the burette. Dilute hydrochloric acid, HCl(aq), (IRRITANT at concentration used) – see CLEAPSS Hazcard HC047a and CLEAPSS Recipe Book RB043.

Read our standard health and safety guidance.Magnesium ribbon, approximately 3–4 cm length.Hydrochloric acid, 2 M, (IRRITANT), 25 cm 3.

Similarly a measurement of room temperature is needed. If a barometer is not available in the laboratory, an up-to-date reading of atmospheric pressure will need to be obtained shortly before the lesson, eg from a local weather website.Using the mass and length of the long piece of magnesium, the average mass of a 3 cm length can be calculated with sufficient accuracy. If a balance weighing to 0.001 g is not available, reasonable results could be obtained by weighing a much longer (eg 30 cm) piece of magnesium ribbon beforehand on a balance weighing to 0.01 g, measuring its length and then cutting it accurately into 3 cm lengths.Refer to CLEAPSS Laboratory Handbook Section 10.10.1.

#ATOMIC MASS OF MAGNESIUM CHLORIDE FREE#

Ensure the burette taps are free from leakage, operate smoothly and are secure in their sockets.

Access to room temperature and pressure measurements (see note 3).

Access to a top-pan balance, accurate to +/– 0.001 g (see note 2).

Including the time taken by the teacher to demonstrate the procedure, and allowing an average of five minutes for each student to weigh their magnesium ribbon, a total of 45 minutes should be adequate for the class to obtain and record their results. Timing will depend on the adequacy of access to top-pan balances, and the skill with which students can use the balance to sufficient accuracy. This is a class experiment suitable for students who already have a reasonable understanding of the mole concept, and are at least beginning to use chemical equations to perform calculations. From this, students can deduce the relative atomic mass of magnesium. They can then use the measured volume of hydrogen gas produced and the mass of magnesium to calculate the mass of magnesium required to produce one mole of hydrogen molecules. In this experiment, students react magnesium ribbon with dilute hydrochloric acid to produce hydrogen gas.

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