A student attempted to identify an unknown compound by the method used in the experiment. She found that when she heated the sample weighing 0.4862g, the mass barely changed, dropping to 0.4855g. When the product was converted to a chloride, the mass went up to 0.5247g. Is the sample a carbonate? What are the two compounds that might be the unknown?

Question

Iyana

Chemistry

14 January, 08:40

A student attempted to identify an unknown compound by the method used in the experiment. She found that when she heated the sample weighing 0.4862g, the mass barely changed, dropping to 0.4855g. When the product was converted to a chloride, the mass went up to 0.5247g. Is the sample a carbonate? What are the two compounds that might be the unknown?

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Melissa Levy · Answer 1

Na2CO3 + 2Cl - ⇒ 2NaCl + CO3^-2

1 mole of Na2CO3 = 106 g

2 moles of NaCl = 2 x 58.4

= 116.8 g

Na2CO3 would increase by 116.8 / 106 = 1.10 to form 2NaCl.

0.4862 g x 1.10 = 0.515 grams of NaCl.

K2CO3 + 2Cl - ⇒ 2KCl + CO3^-2

1 mole of K2CO3 = 138.2 g

2 moles of KCl = 149.1

K2CO3 would increase by 149.1 / 138.2 = 1.079 to form 2KCl

0.4862 x 1.079 = 0.5246 g