Mix and Flow of Matter Unit 1 Grade 8 Science

Question 1

What is a Pure Substance?

Answer 1

Pure Substances are made up of one element, or compound. All of the particles are the same.

Question 2

What is a Homogeneous Mixture?

Answer 2

A mixture that appears to only have one set of properties.

Question 3

What is a Heterogeneous Mixture?

Answer 3

A mixture containing two or more materials that are visible.

Question 4

What is a Suspension?

Answer 4

A type of heterogeneous mixture in which the particles settle after mixing.

Question 5

What is a Colloid?

Answer 5

A type of heterogeneous mixture in which the particles do not settle after mixing.

Question 6

What is a Mechanical Mixture?

Answer 6

A heterogeneous mixture in which materials separate into phases.

Question 7

What is a Solution?

Answer 7

Mixtures that their particles slip in between each other in an even distribution throughout the whole mixture.

Question 8

What is a Fluid?

Answer 8

Something can flow because their particles can move past each other.

Question 9

What is the difference between the particle behavior of solid, liquids, and gasses? (how closely are each packed together)

Answer 9

A solid’s particles are closely packed together, do not move around, and are formed in a pattern.
A liquid’s particles have a little space between them, vibrate, and are formed randomly.
A gasses particles are very far apart, move around quickly, and are also formed randomly.

Question 10

How do you determine and express concentration of a solution

Answer 10

Concentration is the grams of solute per 100 ml of solvent. Must be expressed in terms of 100 ml of solvent.

Question 11

What is “saturation point”

Answer 11

The point at which no more solute can be dissolved at that temperature.

Question 12

What is the difference between a solute and a solvent

Answer 12

A solvent is the substance that does the dissolving. The solvent dissolves the solute to form a solution. A solute is the substance that dissolves. The solute dissolves in a solvent to form a solution. Water is an excellent solvent.

Question 13

What does “rate of dissolving” mean?

Answer 13

The rate of dissolving is how fast a solute will be broken down by a certain solvent.

Question 14

What are the factors that affect a solute’s rate of dissolving and how they increase it.

Answer 14

Temperature- increased energy.
Agitation- increased contact.
Particle Size- increased surface area.

Question 15

Use the particle model to explain the difference in density between solids, liquids, and gasses

Answer 15

Solid particles are more dense because there is little space between them and have more particles than liquids and gasses.
Liquids are more dense than gasses because they have more particles than a gas.
Gasses are the least dense between the three because they have the most space between their particles and have the least amount of particles.

Question 16

How do you identify if a material is more dense or less dense than another

Answer 16

1.Weigh it to find the mass.
2. put it in water to see how much water it displaces
3. Calculate the density by dividing mass by volume.

Question 17

Understand Archimedes’ principle and how to measure the volume of irregularly shaped objects

Answer 17

The Archimedes Principle states that the buoyant force exerted on an object is equal to the weight of the liquid it displaces.
When you take an object and place it in a liquid, it will displace its own volume.

Question 18

how does dissolving a solute in a solvent change the density

Answer 18

The solute will fill some of the empty space between the solvent particles, increasing the mass of a solution while having little effect on the volume.

Question 19

Viscosity vs flow rate

Answer 19

Viscosity describes how well a liquid will flow. It refers to the ¨thickness¨ or ¨thinness¨ of a liquid.
How fast fluid flows is called it´s flow rate. Flow rate will tell us how fast a fluid will flow from one point to another.

Question 20

How does temperature affect viscosity and flow rate?

Answer 20

When the temperature increases and comes into contact with some liquids, the viscosity will decrease and the flow rate will increase.

Question 21

Understand the formula P=F/A

Answer 21

Pressure=Force divided by Area
Force=Pressure multiplied by Area
Area=Force divided by Pressure

Question 22

Understand the difference between hydraulic systems and pneumatic systems

Answer 22

Hydraulic systems use liquids and pneumatic systems use gasses. Liquids can’t be compressed. Gasses can be compressed. Pneumatic systems are fast but weak. Hydraulic systems are slower but stronger.

Question 23

Compare the compressibility of liquids vs gasses

Answer 23

You can compress a gas because the particles of a gas have space between them and they can be squeezed closer together while remaining a gas. The particles of a liquid are too close together, so they cannot be squeezed like the particles of a gas.