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Can't solve this chem problem. Could you guys help me plz?

The problem is from the text book 'Chemistry for Cambridge IGCSE' and on page 11 question 3.

Q: Oxygen is the gas we breathe in. It can be separated from the air. It boils at -219ºC and freezes at -183ºC.
In which state is oxygen, at: ⅰ 0ºC? ⅱ -200ºC?

But what I wonder is that can the boiling point be lower than the melting point ?
In addition, the original boiling point of oxygen is -183ºC and the original melting point of oxygen is -219ºC.
What's the matter with that question? or Am I stupid? :frown:

Could anyone solve this please?

Reply 1

Diana Heo

The question is from a text book 'Chemistry for Cambridge IGCSE' and on page 11 question 3.

Q : Oxygen is the gas we breathe in. It can be separated from the air. It boils at -219ºC and freezes at -183ºC.
In which state is oxygen, at: ⅰ 0ºC? ⅱ -200ºC?

But what I wonder is that can the boiling point be lower than the melting point?
In addition, according to the truths of science, the boiling point of oxygen is -183ºC , not -219ºC. And its melting point is -219ºC, not -183ºC.
What's the matter with this question? or Am I stupid? :frown:

Could anybody solve this please?

(edited 8 years ago)

Reply 2

Nessie162

It's the other way around. Freezing point is -219 and boiling point is -183 :smile:

Reply 3

DougallnDougall

0C - liquid
-200C - somewhere between liquid and solid?
The textbook has the boiling and freezing points wrong way round.

PS - don't take my word for it coz I've never studied chemistry 😜😂😂😂

Reply 4

Little Tail Chaser

It's a typo, it freezes/melts at -218.4°C and boils/condenses at -183.0°C according to here :smile:

You're right that the boiling point can't be lower than the melting point, you're not stupid at all! :smile:

Reply 5

Diana Heo

Original post by Nessie162

It's the other way around. Freezing point is -219 and boiling point is -183 :smile:

Then, the answer would be ' ⅰ Oxygen is still gas at 0ºC. ⅱ Oxygen turns into liquid at -200ºC.'
Is this right ?

Reply 6

Diana Heo

Original post by Little Tail Chaser

It's a typo, it freezes/melts at -218.4°C and boils/condenses at -183.0°C according to here :smile:

You're right that the boiling point can't be lower than the melting point, you're not stupid at all! :smile:

Thank you sooooo much :smile:

Reply 7

Diana Heo

Original post by DougallnDougall

Thanx for your reply :smile:

Reply 8

DougallnDougall

Original post by Diana Heo

Thanx for your reply :smile:

You're welcome but honestly I wouldn't go with my answer unless quite desperate 🙈 Not sure how I even came to know that Oxygen can be boiled and frozen 😕😊

Reply 9

Little Tail Chaser

Original post by Diana Heo

Then, the answer would be ' ⅰ Oxygen is still gas at 0ºC. ⅱ Oxygen turns into liquid at -200ºC.'
Is this right ?

You're correct about it being a gas and a liquid. It won't be 'in between' the two states as suggested above. Pure elements change state at or very close to their boiling/meting points.