#### Boyles law

- Boyle’s law states that the pressure of an ideal gas increases as its container volume decreases.
- The volume of an ideal gas is inversely proportional to its absolute pressure at a constant temperature.

**Equation**

PV = K

Where

P = pressure

V = Volume

K Is the constant

To find pressure or volume, the equation becomes

Pi Vi = Pf Vf

Pi = initial pressure of the gas

Vi = initial volume of the gas

Pf = Final pressure

Vf = Final volume

#### Example. 1

A tank of volume 250 L, is evacuated and connected to a 50 L bulb filled with air. When the two are joined, the air pressure inside the bulb drops to 2.20 atm, while the temperature remains the same. Find the initial pressure In the 50L bulb

##### Solution

In this sample question, we are provided with the initial volume of the bulb, final volume, and final pressure.

Pi Vi = Pf Vf

P initial = ?

V initial = 50 L

P final = 2.20 atm

V final = (50L +250L) = 300 L

We can make P initial the subject of the formula as follows

Pi * 50 = (2.2 * 300)

Pi = (2.2 *300) / 50

Pi = 13.2 atm

The initial pressure of the 50 L bulb is 13.2 atm

## Revision

P1V1=P2V2

What is the formula for Boyle’s Law?

Kelvin (K)

Celcius

Ferenheit

Give three units of Temperature

given

unknown

equation

setup

solve

What does GUESS mean?

T

What is the symbol for temperature?

gay-lussac’s law

P1T2=P2T1

volume

what’s constant in Gay-Lussac’s law?

write down and label all the givens

After reading a gas law problem, what should the first step be in solving?

Direct proportions; one goes up the other goes up. Inverse; one goes up the other goes down.

What is the difference between inverse and direct proportions?

T1V2=T2V1

What is the formula for Charles’ Law?

Boyle’s Law

P1V1=P2V2

Pressure

What is constant in Charles’ Law?

Van der Waal’s equation

What is another name for the real gas law?

Combined gas law

P1V1T2=P2V2T1

A=molecular attraction

B=molecular volume

What two factors of a real gas are not considered in an ideal gas?

P

What is the symbol for pressure?

Diffusion

A ballon deflates over time. What is this an example of?

atm (atmosphere)

torr

kPa (kilopascals)

mmHg (milimeters of mercury)

Give three units of pressure

Temperature

What is constant in Boyle’s law?

P1T2=P2T1

What is the formula for Gay-Lussac’s Law?

ideal gas law

PV=nRT

V

What is the symbol for volume?

Standard temperature and pressure;

273 K, 101.3 kPa, 1.0 atm, 760 mmHg/torr

What is STP?

Dalton’s law (Dalton’s partial pressure law)

Pt=P1+P2+P3…..

mL, L, dm3, cm3

(dm3=L) (cm3=mL)

Give three units of volume

Charles’ Law

T1V2=T2V1

PV=nRT

What is the formula for the combined gas law?

n

What is the symbol for the number of moles?

PV=nRT

What is the formula for ideal gas law?

if the units for pressure or volume changed

Why would the ideal gas law (R) constant change?

Pt=P1+P2+P3…..

What is the formula for Dalton’s Law?

The spreading of molecules from a high concentration to a low concentration. Spraying air freshener or perfume and smelling it from another room or farts.

What is diffusion? Give an example.

22.4 L

How many liters are in a mole of STP?

The combined gas law is called such because it combines Boyles’, Gay-Lussac’s, and Charles’ law.

Why is the combined gas law called such?

amount

What is held constant in a combined gas law?

Temperature; Amount; Pressure; Volume; inversly

Boyle’s law – When ** _ and** are held constant,

**proportional.**

*_ and*are*_*Amount; Pressure; Temperature; volume; directly

Charles’ Law – When **_ and ***are held constant, and _* are directly proportional.

used when givens are estimated for gas

When is STP used?

Pressure

amount

temperature

volume

factors that could affect a gas

used to that all gasses are treated the same way. IT negates molecular attraction and molecular volume

When are Ideal Gases used?

…

ANY LAW WITH TEMPERATURE IN THE EQUATION MUST BE CHANGED INTO KELVIN

homogenous mixture of substances.

What is a solution?

Total pressure exerted by a gas is equal to the sum of the partial pressures of each gas in the solution

What is dalton’s law?

gas formed by the water particles in the air. It is used to determine the opressure of a “dry” gas, using daltons law

What is water vapor and when is it formed?

P+(an^2)/(v^2) = nRT

What is Van der Waal’s equation?

Kelvin and Liters

What should the Volume and Temperature always be in when working with the ideal gas formula?