chemistry question?
2016-01-11 8:58 am
The student used 25 mL of the 6 M HNO3 o 0.6489 g of the alloy. After the sample reacts with the acid, saturated NaCl is used to precipitate the silver out of solution. The precipitate is filtered, washed, dried and weighed. Question number one: How many moles of nitric acid are in 25 mL of 6M HNO3? Question number two: If 0.638 g AgCl were precipitated, what mass of Ag was in the original sample?
回答 (1)
2016-01-11 9:26 am
1.
Number of moles of HNO3
= (6 mol/L) × (25/1000 L)
= 0.15 mol
2.
1 mol of AgCl contains 1 mol of Ag.
(107.9 + 35.45) = 143.35 g of AgCl contains 107.9 g of Ag.
Mass of Ag = (0.638 g) × (107.9/143.35) = 0.480 g
Number of moles of HNO3
= (6 mol/L) × (25/1000 L)
= 0.15 mol
2.
1 mol of AgCl contains 1 mol of Ag.
(107.9 + 35.45) = 143.35 g of AgCl contains 107.9 g of Ag.
Mass of Ag = (0.638 g) × (107.9/143.35) = 0.480 g
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