Req Prac 4 Density Flashcards
Part 1: calculating the density of a regularly shaped object
Outline the basic steps of the practical
- Measure the dimensions of the regular shape and calculate the volume
- Measure the mass of the shape using a calibrated balance
- Calculate density from the mass and volume
Give the formula for the volume of a prism
Volume = area of face x height
What equation is used to calculate volume of a rectangular prism ?
Volume = length x width x height
What equation is used to calculate density?
Density = mass / volume
What unit is ised for density?
kg/m^3
What piece of equipment is used to measure the object’s mass? What must you do before using it ?
A digital balance, which should be zeroed before placing the object on it to avoid a zero error
How do you convert from g/cm^3 to kg/m^3
Multiply the value by 1000
Part 2: calculating the density of a irregulalry shaped object
- Outline the basic steps of the practical
- Measure the mass of the irregular shape
- Fill a displacement can with water and submerge the object
- Record the volume of water that has been displaced
- Calculate the density from the mass and volume
- What should you place under the can spout to collect the water ?
A measuring beaker
- Explain how you should fill the displacement can to get the most accurate results
Fill the can until water starts to drip out of the spout and into the beaker . Wait until the dripping just stops before submerging the object
Part 3: calculating the density of a liquid
- Outline the basic steps of the practical
- Measure the mass of the empty measuring cylinder
- Pour around 100cm^3 of liquid into the cylinder and record the volume
- Measure the mass of the cylinder with liquid in, and subtract the cylinder’s mass to calculate the mass of liquid.
- Calculate density from mass and volume
- How does the density of solids and liquids compare?
In general, solids are more dense than liquids since their particles are more tightly packed together meaning there is more mass per unit volume
