Density

During class today we:

• Checked in homework
• Went over Density Notes
• Got Density Homework

Density is D = m/v or Density = Mass/Volume. To solve a density problem such as the the example in the notes you first substitute what you know into the density equation. In this case, the chocolate bar has a mass of 55.6g and a volume of 30cm^3(Cubed). So start by substituting the mass and volume, D = 55.6g/30cm^3. You then simply just divide the two by using your calculator. When entered into your calculator you get, 1.8533333. According to the significant figure rule for multiplying or dividing you round to 3 sig figs. You then get 1.85g/cm^3.

Some other questions might give you the density and ask you for something else. In this case use simple algebra to solve. An example of this can also be found on the notes. This example states that that silver has a density of 10.5g/cm^3, it also states it has a mass of 25g and asks you to find the volume. First, set up your equation, 10.5g/cm^3 = 25g/v. To figure out the volume solve for v. To do this first multiply both sides by v. You then get 10.5v = 25. Then simply divide by 10.5. You get 2.380952.... round to 3 sig figs. Finally you get, 2.38cm^3.

The notes sheet and the homework for tonight can be found on moodle.

Density WILL be on the quiz tomorrow so be ready.

HW: Density sheet, study for quiz tomorrow.

The next scribe will be Jake A.