We have a physics question posted by victor ejeakachidav as follows:
A gas has a volume of 500cm3 when a pressure of 76mmHg is exerted on it. What will be the volume if the pressure changes to 73mmHg assuming temperature remains constant?
I believe some of us smarter ones already has the answer for this. But, let's analyse the question before answering it as what good scientists will do to be careful in our thinking process!
This question talks about a given volume and pressure of gas. Then, it asks what the new volume will be if the pressure changes GIVEN AND ONLY GIVEN that temperature REMAINS CONSTANT!!
Haha! This question is a give away as some of us have learnt about Boyle's Law in physics. Just a note here: Some local Singapore schools do not teach Boyle's Law while some schools teach. Well, if you are keen to know how Boyle's Law works, read on!!
According to wikipedia.........product of pressure and volume is a constant for a given mass of confined gas as long as the temperature is constant. For comparing the same substance under two different sets of condition, the law can be usefully expressed as
P1V1 = P2V2
So, Boyle's Law is referring to a gas of a fixed mass. The gas can be of a certain pressure P1 and volume V1 at first. If we change the pressure to a new pressure P2, the volume V2 will also be expected to change. But, the product P1V1 will always be equal to product P2V2. This is PROVIDED THE TEMPERATURE OF THE GAS MUST BE CONSTANT!
Well, the scientist Boyle observed and described this phenomenon concerning gases. So, it is named after him as Boyle's Law. From Boyle's Law, we understand that as gas volume increases, gas pressure decreases. As gas volume decreases, gas pressure increases. This will be true only if temperature remains constant. For those interested to explore more of Boyle's Law, there is a link at the bottom of this post.
Well. Let's solve this question now since we know we are using Boyle's Law formula.
P1V1 = P2V2
76 X 500 = 73 X V2 , recall in the question first pressure was V2 = 521 cm3 76mmHg and first volume was 500 cm3.
Second pressure was 73 mmHg. We put the values into the formula.
So, the volume will be 521 cm3.
A note on the answer: Notice that the volume increased from 500 cm3 to 521 cm3. This is because the first pressure has decreased from 76 mmHg to second pressure 73 mmHg which is lower. So, volume will increase from 500 cm3 to 521 cm3 which is in inverse proportion. This is how fixed mass of gases behave under constant temperature in terms of their pressures and volumes described by scientist Boyle.
Thanks victor ejeakachidav for asking this question so we can all discuss and learn from it! =)
Click link for video on Boyle's Law.
A gas has a volume of 500cm3 when a pressure of 76mmHg is exerted on it. What will be the volume if the pressure changes to 73mmHg assuming temperature remains constant?
I believe some of us smarter ones already has the answer for this. But, let's analyse the question before answering it as what good scientists will do to be careful in our thinking process!
This question talks about a given volume and pressure of gas. Then, it asks what the new volume will be if the pressure changes GIVEN AND ONLY GIVEN that temperature REMAINS CONSTANT!!
Haha! This question is a give away as some of us have learnt about Boyle's Law in physics. Just a note here: Some local Singapore schools do not teach Boyle's Law while some schools teach. Well, if you are keen to know how Boyle's Law works, read on!!
According to wikipedia.........product of pressure and volume is a constant for a given mass of confined gas as long as the temperature is constant. For comparing the same substance under two different sets of condition, the law can be usefully expressed as
P1V1 = P2V2
So, Boyle's Law is referring to a gas of a fixed mass. The gas can be of a certain pressure P1 and volume V1 at first. If we change the pressure to a new pressure P2, the volume V2 will also be expected to change. But, the product P1V1 will always be equal to product P2V2. This is PROVIDED THE TEMPERATURE OF THE GAS MUST BE CONSTANT!
Well, the scientist Boyle observed and described this phenomenon concerning gases. So, it is named after him as Boyle's Law. From Boyle's Law, we understand that as gas volume increases, gas pressure decreases. As gas volume decreases, gas pressure increases. This will be true only if temperature remains constant. For those interested to explore more of Boyle's Law, there is a link at the bottom of this post.
Well. Let's solve this question now since we know we are using Boyle's Law formula.
P1V1 = P2V2
76 X 500 = 73 X V2 , recall in the question first pressure was V2 = 521 cm3 76mmHg and first volume was 500 cm3.
Second pressure was 73 mmHg. We put the values into the formula.
So, the volume will be 521 cm3.
A note on the answer: Notice that the volume increased from 500 cm3 to 521 cm3. This is because the first pressure has decreased from 76 mmHg to second pressure 73 mmHg which is lower. So, volume will increase from 500 cm3 to 521 cm3 which is in inverse proportion. This is how fixed mass of gases behave under constant temperature in terms of their pressures and volumes described by scientist Boyle.
Thanks victor ejeakachidav for asking this question so we can all discuss and learn from it! =)
Click link for video on Boyle's Law.