posted by .

the crucible is not fired, as the procedure suggests, but had retained some impurities from previous use(or it could be oily smudges from fingers). the mass of the "dirty" crucible is recorded. however the impurities are burned off in the experiment. how does this affect the reported mass of the final product? explain

• What ?? -

This must be a chemistry question and you gave VERY little evidence of what you are working on. However, in general, let's make up some numbers.
15.00 g = clean xble
17.00 g = xble + our ppt
----------
2.00 g = mass ppt.

BUT suppose the xble is dirty, as the problem suggests, so it actually weighs 16.00 g = mass clean xble + dirt
When we add the ppt to the dirty xble, we have
15.00 clean xble
1.00 g dirt
2.00 g ppt
-----
Total 18.00 g

Now we fire it, the dirt burns off and it will weigh
15.00 g for clean xble
+2.00 for ppt
Total is 17.00
and when we subtract 17.00-16.00 = 1.00 g ppt which of course is wrong. We actually had 2.00 g ppt; therefore, the mass of the reported material is too low.

## Similar Questions

1. ### Filtration?

Question: While performing a crystallization, you obtain a light tan solution after dissolving your crude product in hot solvent. A decolorizing step is determined to be unnecessary, and there are no solid impurities present. Should …
2. ### Chemistry

I know how to find a and b on this problem but how do I find c?
3. ### Chemistry

If some volatile impurities in the crucible are removed from the hydrated MgSO4 along with the water, is the reported mass of water removed too high or too low. Explain.
4. ### Chemistry

if some volatile impurities in the crucible are not burned off in step 1 but are removed in step 4 is the reported percent mass of water in the hydrated salt too high or too low?
5. ### chemistry

A crucible containing potassium chlorate has a mass is 24.426 g. The crucible is heated according to the lab procedure for this week's experiment and is found to weigh 23.642 g. Write an equation for the reaction and, assuming that …
6. ### chemistry

A crucible containing potassium chlorate has a mass is 24.426 g. The crucible is heated according to the lab procedure for this week's experiment and is found to weigh 23.202 g. Write an equation for the reaction and, assuming that …
7. ### Chemistry Lab

In chemistry we are doing a lab that involves crucibles and Mg ribbon, we have three days to complete the lab. Anyways do you think it would be alright to substitute the mass of the crucible we had the first day with the mass of the …
8. ### Chem

The crucible is handled with oily fingers after its mass measurement but before the 3 gram sample of the hydrated salt is measured. Subsequently, in part B.1, the oil from the fingers is burned off. Will the percent water in the hydrated …
9. ### CHEMISTRY

is this right? 5. After heating the crucible is set on the lab bench where it is contaminated with the cleaning oil used to clean the lab bench but before its mass is measured. The analysis continues where the mass of the anhydrous
10. ### chem

The crucible is handled with oily fingers after its mass measurement but before the 3 gram sample of the hydrated salt is measured. Subsequently, in part B.1, the oil from the fingers is burned off. Will the percent water in the hydrated …

More Similar Questions