Principles of Gravimetric Analysis

Question

Consider the following data from a gravimetric analysis experiment.

| Description | Mass (g) |
|---|---|
| Unknown Alkali Hydroxide Sample | 4.33 |
| $$Cu(OH)_2$$ precipitate | 3.81 |

Reaction: $$Cu^{2+}+2\,OH^-\rightarrow Cu(OH)_2$$

All of the following statements regarding the experiment are true EXCEPT:

Accepted Answer

The mass of $$Cu(OH)_2$$ precipitate exceeding the original sample mass would violate conservation of mass.

Answer

The balanced reaction $$Cu^{2+}+2\,OH^-\rightarrow Cu(OH)_2$$ is used to relate moles of hydroxide to precipitate formed.

Answer

Gravimetric analysis relies on the law of conservation of mass to correlate precipitate mass with the amount of the analyte.

Answer

Errors in weighing the precipitate can lead to incorrect determination of the unknown compound.

Rank	User	Correct Count	Attempt Count	Total Time	Score
#1	lhormacero	1	1	1m 15s	25
#2	sadie.e.gorr	0	1	0m 00s	-10
#3	mahima6129	1	4	4m 18s	-188

Description	Mass (g)
Unknown Alkali Hydroxide Sample	4.33
$Cu(OH)_2$ precipitate	3.81

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