Sig figs problem (chem) (1 Viewer)

[indeed]

Could I get some opinions on how many sig figs should be rounded for this q? (i think it's 1 sig fig because the 100mL, but the q says 3 s.f.)

 

[...xD]

View attachment 37681
Could I get some opinions on how many sig figs should be rounded for this q? (i think it's 1 sig fig because the 100mL, but the q says 3 s.f.)

Take this with a grain of salt but I think it should be 3s.f. because (in physics at least), you assume the most amount of s.f. in the number with the least possible amount of s.f.

E.g. between 100, 25 and 0.173,

100 has max 3 and min 1

25 has 2

0.173 has 3

So we take bare min: 1 which is 100 and then assume its the most no. of s.f: 3

+ the question also says to 3.s.f. so most likely to 3s.f.

 

[indeed]

Take this with a grain of salt but I think it should be 3s.f. because (in physics at least), you assume the most amount of s.f. in the number with the least possible amount of s.f.

E.g. between 100, 25 and 0.173,

100 has max 3 and min 1

25 has 2

0.173 has 3

So we take bare min: 1 which is 100 and then assume its the most no. of s.f: 3

+ the question also says to 3.s.f. so most likely to 3s.f.

Oh ok, I didn't know about the process of taking the minimum and using maximum, normally I just found smallest sig figs. Thank you!

 

[synthesisFR]

you assume the most amount of s.f. in the number with the least possible amount

to me this doesn't really make sense
e.g. in "100" there is only 1 sig fig, u can't say there are many possibilities that just ruins the whole point of sf in the first place
what do u mean by the most amount of sig fig in the number with the least possible amount ???
its always the lowest amount of sig fig, thats it.

 

[indeed]

to me this doesn't really make sense
e.g. in "100" there is only 1 sig fig, u can't say there are many possibilities that just ruins the whole point of sf in the first place
what do u mean by the most amount of sig fig in the number with the least possible amount ???
its always the lowest amount of sig fig, thats it.

Yeah that makes more sense in my head, but Ieaving 1 s.f. as the final answer also seems a bit uncomfortable

 

[cossine]

to me this doesn't really make sense
e.g. in "100" there is only 1 sig fig, u can't say there are many possibilities that just ruins the whole point of sf in the first place
what do u mean by the most amount of sig fig in the number with the least possible amount ???
its always the lowest amount of sig fig, thats it.

The thing is whether you can measure something or not. If you could only measure to the nearest 100 ml then yes 1 s.f. would make sense. If you could measure nearest 1ml then 3 s.f. would make sense

 

[wizzkids]

Excuse me?
Where does it say in the question that any calculation is required?
The question appears to be asking for a qualitative answer, not a quantitative answer.
Or have I missed something?
However, the data is ambiguous. The number of significant figures in the number "100" is ambiguous. Trailing zeros are not significant unless there is a trailing decimal point.
That is the rule, but if the question states to use 3 sig.figs then use 3. Don't read too much into the question.

 

[synthesisFR]

The thing is whether you can measure something or not. If you could only measure to the nearest 100 ml then yes 1 s.f. would make sense. If you could measure nearest 1ml then 3 s.f. would make sense

yeah i agree (and thats the whole reason sig figs were invented!)
but in the context of these questions what would u assume? I was always told by all of my teachers to assume lowest amount of sig fig unless obviously if the question specifies how much they want, which is why i would go with 1 sig fig

 

[synthesisFR]

Excuse me?
Where does it say in the question that any calculation is required?
The question appears to be asking for a qualitative answer, not a quantitative answer.
Or have I missed something?
However, the data is ambiguous. The number of significant figures in the number "100" is ambiguous. Trailing zeros are not significant unless there is a trailing decimal point.
That is the rule, but if the question states to use 3 sig.figs then use 3. Don't read too much into the question.

the question might have multiple parts but he only sent the main information part of the question which is why he's asking ig
but if there aren't any following parts that involve calculations then we've all been discombobulating our brains for nothing Lol.

 

[jimmysmith560]

For reference, the full version of this question is as follows:

A 100 mL saturated solution of calcium hydroxide at 25°C contains 0.173 g of calcium hydroxide.

(a) Calculate the solubility product (K_sp) of this salt at 25°C. (b) Explain why the undissolved solid is not included in the expression for the solubility product constant. (3 marks)

(b) Explain why the undissolved solid is not included in the expression for the solubility product constant. (1 mark)

One thing to note is that this version of the question (which comes from NESA's additional sample examination questions for Chemistry) does not specify a number of significant figures, contrary to OP's version of the question.

I will also include a sample answer to part (a), hoping that it would contribute to this discussion:

 

[indeed]

Excuse me?
Where does it say in the question that any calculation is required?
The question appears to be asking for a qualitative answer, not a quantitative answer.
Or have I missed something?
However, the data is ambiguous. The number of significant figures in the number "100" is ambiguous. Trailing zeros are not significant unless there is a trailing decimal point.
That is the rule, but if the question states to use 3 sig.figs then use 3. Don't read too much into the question.

It's mainly a qualitative question which requires quantitative evidence, the answers have it in 3 s.f., though the trailing zeros rule you mentioned makes more sense

 

[indeed]

the question might have multiple parts but he only sent the main information part of the question which is why he's asking ig
but if there aren't any following parts that involve calculations then we've all been discombobulating our brains for nothing Lol.

Yeah the question requires quantitative evidence for a relatively qualitative question

 

[indeed]

For reference, the full version of this question is as follows:

A 100 mL saturated solution of calcium hydroxide at 25°C contains 0.173 g of calcium hydroxide.

(a) Calculate the solubility product (K_sp) of this salt at 25°C. (b) Explain why the undissolved solid is not included in the expression for the solubility product constant. (3 marks)

(b) Explain why the undissolved solid is not included in the expression for the solubility product constant. (1 mark)

One thing to note is that this version of the question (which comes from NESA's additional sample examination questions for Chemistry) does not specify a number of significant figures, contrary to OP's version of the question.

I will also include a sample answer to part (a), hoping that it would contribute to this discussion:

View attachment 37683

Thank you