Download presentation

1
The Combined Gas Law

2
**Manipulating Variables in equations**

Often in an equation we want to isolate some variable, usually the unknown From math: what ever you do to one side of an equation you have to do to the other side Doing this keeps both sides the same E.g. x + 5 = 7, what does x equal? We subtract 5 from both sides … x + 5 – 5 = 7 – 5, thus x = 2 Alternatively, we can represent this as 5 moving to the other side of the equals sign … x + 5 = 7 becomes x = 7 – 5 or x = 2 Thus, for addition or subtraction, when you change sides you change signs

3
**Multiplication and division**

We can do a similar operation with multiplication and division E.g. 5x = 7, what does x equal? We divide each side by 5 (to isolate x) … 5x/5 = 7/5 … x = 7/5 … x = 1.4 Alternatively, we can represent this as 5 moving to the other side of the equals sign … 5x = 7 becomes x = 7/5 Thus, for multiplication and division, when you change sides you change position (top to bottom, bottom to top)

4
**Multiplication and division**

Let’s look at a more complicated example: (x) (y) 5 = 7a b Isolate a in the equation: Move b to the other side (from bottom to top) 5 b (x) (y) = 7a Move 7 to the other side (from top to bottom) (x)(y)(b) 5 = 7a (x)(y)(b) (35) = a (x)(y)(b) (5)(7) = a or

5
**Multiplication and division**

This time, isolate b in the equation: (x) (y) 5 = 7a b Move b to the other side (it must be on top) … (x) (y) 5 = 7a b Move everything to the other side of b 35a xy = b (b)(x)(y) 5 = 7a Q - Rearrange the following equation to isolate each variable (you should have 6 equations) P1V1 P2V2 T T2 =

6
**Combined Gas Law Equations**

P1 = P2T1V2 T2V1 P2 = P1T2V1 T1V2 T1 = P1T2V1 P2V2 T2 = P2T1V2 P1V1 V1 = P2T1V2 T2P1 V2 = P1T2V1 P2T1

7
**These are all subsets of a more encompassing law: the combined gas law**

Combining the gas laws So far we have seen two gas laws: Robert Boyle Jacques Charles Joseph Louis Gay-Lussac V1 T1 = V2 T2 P1 T1 = P2 T2 P1V1 = P2V2 These are all subsets of a more encompassing law: the combined gas law P1V1 P2V2 T T2 = Read pages 437, Do Q 26 – 33 (skip 31)

8
**Q 26 V1 = 50.0 ml, P1 = 101 kPa V2 = 12.5 mL, P2 = ? T1 = T2 P1V1 T1 =**

(101 kPa)(50.0 mL) (T1) = (P2)(12.5 mL) (T2) (101 kPa)(50.0 mL)(T2) (T1)(12.5 mL) = 404 kPa = (P2) Notice that T cancels out if T1 = T2

11
**Q 27 V1 = 0.10 L, T1 = 298 K V2 = ?, T2 = 463 P1 = P2 P1V1 T1 = P2V2**

(P1)(0.10 L) (298 K) = (P2)(V2) (463) (P1)(0.10 L)(463 K) (P2)(298 K) = 0.16 L = (V2) Notice that P cancels out if P1 = P2

12
**Q 28 P1 = 150 kPa, T1 = 308 K P2 = 250 kPa, T2 = ? V1 = V2 P1V1 T1 =**

(150 kPa)(V1) (308 K) = (250 kPa)(V2) (T2) (250 kPa)(V2)(308 K) (150 kPa)(V1) = 513 K = 240 °C = (T2) Notice that V cancels out if V1 = V2

13
Q 29 P1 = 100 kPa, V1 = 5.00 L, T1 = 293 K P2 = 90 kPa, V2 = ?, T2 = 308 K P1V1 T1 = P2V2 T2 (100 kPa)(5.00 L) (293 K) = (90 kPa)(V2) (308 K) (100 kPa)(5.00 L)(308 K) (90 kPa)(293 K) = 5.84 L = (V2) Note: although kPa is used here, any unit for pressure will work, provided the same units are used throughout. The only unit that MUST be used is K for temperature.

14
Q 30 P1 = 800 kPa, V1 = 1.0 L, T1 = 303 K P2 = 100 kPa, V2 = ?, T2 = 298 K P1V1 T1 = P2V2 T2 (800 kPa)(1.0 L) (303 K) = (100 kPa)(V2) (298 K) (800 kPa)(1.0 L)(298 K) (100 kPa)(303 K) = 7.9 L = (V2)

15
**For more lessons, visit www.chalkbored.com**

Q 32 P1 = 6.5 atm, V1 = 2.0 mL, T1 = 283 K P2 = 0.95 atm, V2 = ?, T2 = 297 K P1V1 T1 = P2V2 T2 (6.5 atm)(2.0 mL) (283 K) = (0.95 atm)(V2) (297 K) (6.5 atm)(2.0 mL)(297 K) (0.95 atm)(283 K) = 14 mL = (V2) 33. The amount of gas (i.e. number of moles of gas) does not change. For more lessons, visit

Similar presentations

Presentation is loading. Please wait....

OK

Solving Gas Law Problems Copyright Sautter 2003.

Solving Gas Law Problems Copyright Sautter 2003.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google

Ppt on company law board Topics for ppt on environment Ppt on landing gear system for motorcycles Ppt on five generation of computers Ppt on english grammar tenses Ppt on regular expression generator Ppt on the road not taken interpretation Ppt on search engine google Ppt on atm machine working Ppt on hostel management system in c