Density Of Water Lab

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Discussion
As you know, Density is an intensive physical property. Therefore, as long as you have the same substance in the same phase, the density is the same. There is an equation for determine density, D = m/V where m -mass of substance and V - volume of substance. From a particle view of matter (KMT), density is simply how close (in space) the base units (i.e. particles) are to each other. So, if you have the same substance, going thru the different phases (solid, liquid and gas) the relative densities make sense knowing the gas can go anywhere (have obtained enough energy to overcome their Intermolecular Force) so they will be farthest apart (lowest Density), next closer is liquid (with a higher Density) and finally solids that are the closest (thereby having highest Density).

Of course, there are always exceptions to trends and the most common one here is water. Water's liquid phase is denser than it s solid phase (a reverse of most of there substance). The reason for this is the characteristic of the particles ( IMF & shape). As you know or will know later in the year, water is a polar molecule which means it exerts a Coulombic force onto other water molecules (or anybody else). Also due to the shape of the molecule (a bent shape which you either know or will learn later). From this shape and IMF, water molecules arrange themselves in a hexagonal arrangement when it forms the solid phase (we call it ice). This hexagonal arrangement occupies more space/volume per molecule than in the liquid phase (where the molecules can move freely in 3-D space). So, this is why ice floats in water!

Procedures
This lab is broken into two sections Half the groups will start with 1st section then do the 2nd section and the other half will do the reverse.

Using a Graduated Cylinder
1. Obtain a 25 mL graduated cylinder and Triple beam balance (same balance is used in each section), mass the cylinder and record the mass in your data table..
2. Using the scale on the cylinder, measure out as close as possible 23 ml (or it could 23.00mL) and record the actual volume (remember use sig fig rules when you are determining number)
3. Using the balance, mass the cylinder and water and record that in your data table.
4. Pour the water out of the cylinder and down the sink and put cylinder back on the drying rack.

Using a 100mL Beaker
1. Obtain a 100 mL beaker and Triple beam balance (same balance is used in each section), mass the beaker and record the mass in your data table..
2. Using the scale on the side of the beaker, measure out as close as possible to 23 ml (or it could 23.00mL) and record the actual volume (remember use sig fig rules when you are determining number)
3. Using the balance, mass the beaker and water and record that in your data table.
4. Pour the water out of the beaker and down the sink and put beaker back in the drying bucket.

Calculations: Density of water in g/ml. Make sure that your differences are done in Step 2 (when you should what information you have).

Questions/problems: Questions for Density of Water Lab