## anonymous one year ago what would be the pressure of a given mass of a gas, if its volume and temperature are doubled ............. ?

1. JoannaBlackwelder

P1V1/T1=P2V2/T2 when mass is constant.

2. JoannaBlackwelder

What happens when we sub in 2V1 for V2

3. JoannaBlackwelder

And 2T1 for T2?

4. anonymous

He wants to complement the question one word

5. JoannaBlackwelder

Ok, we are getting there.

6. anonymous

so the answer : mass is constant.?

7. JoannaBlackwelder

No, that is an assumption, since we aren't told how it will change.

8. JoannaBlackwelder

Do you see how when the volume is doubled, that would be 2 times the original volume?

9. anonymous

yes

10. JoannaBlackwelder

Ok, cool. And the same for temp?

11. anonymous

yup

12. JoannaBlackwelder

Ok, so, can you plug those into the equation?

13. anonymous

P1V1/T1=P2V2/T2

14. JoannaBlackwelder

That is the original equation. Can you plug in the other expressions we came up with?

15. anonymous

I don't understand sorry

16. JoannaBlackwelder

It's cool. So, since V2 can be represented by 2V1, P1V1/T1=P2(2V1)/T2

17. JoannaBlackwelder

Does that step make sense?

18. anonymous

yes

19. JoannaBlackwelder

:-) Can you try plugging in the expression for T2?

20. anonymous

T2= P1V2T1/P2V1

21. JoannaBlackwelder

Not solve, substitute.

22. Melodious

joanna

23. anonymous

:c

24. Melodious

that question i didnt understand

25. Melodious

:c

26. anonymous

He wants to complement the question one word

27. Melodious

ur a boy?

28. anonymous

yup

29. JoannaBlackwelder

P1V1/T1=P2(2V1)/(2T1) Do you see how I subbed that in?

30. JoannaBlackwelder

Since T2 is 2T1

31. anonymous

oh, yeah

32. JoannaBlackwelder

:-) So, can you simplify?

33. anonymous

no :c

34. anonymous

I can't :c

35. Melodious

36. Melodious

pls say

37. JoannaBlackwelder

|dw:1434392830978:dw|

38. JoannaBlackwelder

I meant |dw:1434392864965:dw|

39. Melodious

nice idea jo!!!

40. JoannaBlackwelder

Thanks. :-) The 2's cancel|dw:1434392913865:dw|

41. JoannaBlackwelder

Does that make sense?

42. Melodious

yeah

43. Melodious

but which grade chemistry is this?????????

44. JoannaBlackwelder

That's good, @Melodious but I was asking @soso707

45. anonymous

yes @JoannaBlackwelder

46. Melodious

47. JoannaBlackwelder

Great! So we are to |dw:1434393062140:dw|

48. JoannaBlackwelder

Any ideas from here?

49. Melodious

nope i think

50. anonymous

no complete

51. JoannaBlackwelder

Please give it a shot. It is against policy to just give you the answers and we are mighty close to the answer.

52. anonymous

Gay-Lussac's law ?

53. JoannaBlackwelder

No, we just need to simplify what we have so far.

54. JoannaBlackwelder

Using algebra

55. anonymous

|dw:1434393687091:dw|

56. JoannaBlackwelder

Where did the equals sign go?

57. anonymous

We unite place.

58. JoannaBlackwelder

I don't understand what you mean.

59. anonymous

I mean T1

60. JoannaBlackwelder

I still don't understand what you are trying to say. Can you show me?

61. anonymous

|dw:1434394032412:dw|

62. JoannaBlackwelder

Hm, no, the equals sign can't just disappear.

63. anonymous

so wahat ?

64. JoannaBlackwelder

If we multiply both sides by T1, what happens? |dw:1434394220901:dw|

65. anonymous

aha

66. JoannaBlackwelder

:-)

67. anonymous

There will be less pressure?

68. JoannaBlackwelder

How do you get that?

69. anonymous

just I think that

70. JoannaBlackwelder

No, that's not what I get.|dw:1434395143188:dw|

71. JoannaBlackwelder

|dw:1434395174203:dw|

72. anonymous

yeah

73. JoannaBlackwelder

Is there anything else that can cancel?

74. anonymous

I think, no

75. anonymous

or V1?

76. JoannaBlackwelder

Right, great!

77. JoannaBlackwelder

So, what does that leave us with?

78. anonymous

P1=P2

79. JoannaBlackwelder

:-)

80. anonymous

so what now ?

81. JoannaBlackwelder

What do you think that means?

82. anonymous

that the pressure same ?

83. JoannaBlackwelder

Yep

84. anonymous

so : what would be the pressure of a given mass of a gas, if its volume and temperature are doubled same pressure ?

85. JoannaBlackwelder

Yep, or "pressure is constant"

86. anonymous

thanks a lot @JoannaBlackwelder :)

87. JoannaBlackwelder

You're very welcome :-)