__Tutorial – Boyle’s Law Problems__**(Std 4c)**

Read through this tutorial
very carefully. It has almost everything
that needs to be done in the most difficult of problems and goes through the
logic of why each step needs to be donel. I hope this helps!!!!

Using
Boyle’s Law: **P _{1}V_{1}
=**

Stated another way: **PV = k** (k is a constant)

**P _{1}** is the

If P_{1} is given in **atm** and P_{2} is given in **mmHg**, you
must convert **mmHg** to **atm****,**

**OR** convert **mmHg
**to **atm**** **so that ** both pressures
have the same unit of measure**.

Also, if **V**_{1} is given in
**liters** and **V**_{2} is given in **ml** then you must convert **liter **to
**ml**

**OR** convert **ml** to **liter**
so the ** both volumes have the same unit of measure**.

So, Boyle’s Law tells us how ** changing
pressure** will affect

**Example:**

If you have P_{1}
= 235 kPa and
P_{2} = 9,500. Torr and V_{1} = 925 ml, what will V_{2}
be?

**Solution:**

You
must first change **235**** kPa** to **Torr** ( P_{1} ) so that P_{1}
and P_{2} are in the same

units of measure **and**
we have to change **kPa**
to **Pa** before we can change to **atm**.

. 1000 Pa = 1 kPa **and** 101,325 Pa = 1 atm **and** 1 atm = 760 Torr

Use this string of equalities to convert any unit of
pressure to any other in one conversion because __any one__ of these
equalities is equal to __any other__ equality in the string:

**1 atm = 101 kPa = 14.7 psi = 760 Torr = 760 mmHg**

235 kPa 760 Torr

------------ x
-------------- = 1,768 Torr = **P _{1}**

1 101 kPa

Now we have everything
we need to use Boyle’s Law

** P _{1} x V_{1} = P_{2} x
V_{2}**

1,768 Torr x
925 ml = 9,500. Torr x
V_{2}

Divide both sides by 1 Torr to get rid of that unit of measure and also divide
both

sides by 9,500. Torr to get
that number to the left side of the equation.
Now the equation

looks like this:

1,768 x 925 ml

-----------------
= V_{2} **Answer: V _{2} =
172 ml ** (after rounding)

9,500.