Anonymous

# 化學實驗(英文)

to find the relative atomic mass of magnesium by a gas volumes method.

Discussion

1.suggest why the tutor&#039;s estimate of the total mass of the magnesium used by the class is likely to be more accurate than the mass obtained by each student.

2.suggest some sources of error in this experiment

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Update 2:

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to find the relative atomic mass of magnesium by a gas volumes method.

Determination of the relative atomic mass of magnesium

Method 1 - RSULTS: Assume that 1 mole of gas occupies 24 000 cm3 at room temperature and pressure.

Mg(s) + 2HCl (aq) --> MgCl2(aq) + H2 (g)

Calculate the number of moles of hydrogen you collected.

Mg(s) + 2HCl (aq) --> MgCl2(aq) + H2 (g)

Ratio Magnesium: Hydrogen is 1:1

Number of moles = Amount of hydrogen produced / 24000 Hydrogen = 142 / 24000 = 0.00592 moles

Deduce the number of moles of magnesium Number of moles = 1 x 0.00592 Magnesium =0.00592 moles

Calculate the relative atomic mass of magnesium RAM = Mass / Number of moles = 0.12 / 0.00592 = 20.27

Method 2 - RESULTS Mass (g) Weight of clean evaporating basin 31.70 Weight of evaporating basin + conical flask contents 41.64 Weight of evaporating basin + solid magnesium chloride 32.22

Calculate the mass of magnesium chloride formed Weight of evaporating basin and - Weight of clean evaporating basin solid magnesium chloride = 32.22 - 31.70 = 0.52 g Calculate

Discussion

1.suggest why the tutor's estimate of the total mass of the magnesium used by the class is likely to be more accurate than the mass obtained by each student.

我認為是因為老師的經驗與細心程度相較於學生更來的紮實,故老師算的數據較精確

2.suggest some sources of error in this experiment

至於實驗誤差的話,可分人為因素跟自然(儀器.設備)因素

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• Anonymous
6 years ago

你厭倦往返補習班浪費的時間和體力嗎

你想在家裡躺在沙發，就可以上課嗎?

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學員踴躍分享行動補習帶來的便利與效果，累積許多佳績見證。

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