We can measure mass by using a balance or a digital scale Volume Volume is a measurement of the amount of space occupied by the substance How can we measure volume Liquids can be measured using a measuring cup or a graduated cylinder ID: 661649
Download Presentation The PPT/PDF document "Density Unit 2 Fluids Mass" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Density
Unit 2 FluidsSlide2
Mass
We can measure
mass
by using a balance or a digital scale. Slide3
Volume
Volume
is a measurement of the amount of space occupied by the substance.
How can we measure volume?
Liquids
can be measured using a measuring cup or a graduated cylinder. Slide4
Volume
Gases
can be determined by measuring the volume of the container it is in.
I
rregular solids
can be determined by immersing them into a beaker of water and measuring the volume of the displaced fluid.
Displacement
is the amount of space that an object takes up when placed in a fluid.Slide5
Volume
4.
Regular solids
can be determined by measuring the length, width, and height:
V = l × w × h.Slide6
How to Calculate Density
Density (D) =
Mass (m)
or simply, D=
_m
Volume V
Or V=
m
and m = V x D
DSlide7
Sample Problem
Find the density of a 10 g mass of a substance that has a volume of 2.0 cm
3
.
D =
m
D=
10g
= 5 g/
cm
3
V
2.0 cm
3Slide8
Sample Problem
You want to put 10.0 g of salt into a container. If the density of salt is 2.16 g /cm
3
, what is the volume of the container if the salt completely fills it?
V=
m
V=
10.0 g
V=
4.6
g/cm
3
D 2.16 g/cm
3Slide9
Sample Problem
What is the mass of 1500 mL of helium, if the density of helium is 0.0002 g/mL?
m= D x V m= 0.0002 g/mL x 1500 mL m= 0.3 gSlide10
Changes in Density
As Temperature Increases
↓
Particles Gain Energy
↓
Particles spread out
↓
Decrease in Density
As Temperature Decreases
↓
Particles Lose Energy
↓
Particles closer together
↓
Increase in DensitySlide11
Examples of Changes in Density
Hot Air Balloons
(intentional change)
a gas burner that heats the air inside the balloon
particles gain energy and spread further apart
the density of air inside the balloon decreases (less dense than air surrounding the balloon)
so it rises
pilot controls the altitude of the balloon by controlling the amount of heat Slide12
Examples of Changes in Density
Warm vs. Cool Tire
Pressure (natural change)
Tires on an automobile need more air during the winter than they do during the summer.
Winter
as the temperatures decrease particles lose energy and take up less space.
the density of the air decreases, and the tire deflates a little
Summer
increasing temperatures increases particle energy (spread further apart)
air in the tire expands
tire inflatesSlide13
Examples of Changes in Density
water in its three states – natural change
Most substances are denser in their solid state than in their liquid state; water is an exception
when water freezes, it expands and its density decreases (this is why ice floats)
otherwise, water follows the normal trendSlide14
Examples of Changes in Density
drying of wood (seasoning of wood) – natural change
freshly cut wood from a living tree is much heavier than wood that has been cut and dried in the air
water evaporates and is replaced with air
air is much less dense than water, so dry wood is less dense than moist wood (and easier to burn)Slide15
Examples of Changes in Density
salt water being easier to float in – natural change
much easier to float in salt water than in fresh water
the density of salt water is greater than that of fresh water