Matter, Density, Relative Density

What are the three common states of matter?

Solid, Liquid, and Gas.

What is the definition of a brittle solid?

A brittle solid will break without bending

Define ductility in solids.

Ductile materials may be stretched or drawn into shape when cold.

What does it mean if a solid is described as malleable?

A malleable solid can be beaten, rolled, or squeezed into shape.

What is meant by a solid being tenacious?

A tenacious solid resists deformation and is strong.

Explain adhesion in liquids.

Adhesion is the attraction between unlike molecules.

What is cohesion in the context of liquids?

Cohesion is the attraction between like molecules.

Define capillary action.

Capillary action is the tendency of an adhesive fluid to flow into small cracks.

What does fluidity refer to in liquids?

Fluidity is the ability of a liquid to flow.

What does it mean for a liquid to be incompressible?

An incompressible liquid cannot be compressed to lower volume.

What is viscosity?

Viscous refers to the resistance to flow or friction in a liquid.

Define surface tension in liquids.

Surface tension is the surface 'skin' that forms on a liquid due to cohesive forces.

What does it mean for gases to be compressible?

Compressible gases can be compressed to occupy a smaller volume.

Explain diffusion in gases.

Diffusion is the rapid and effortless mixing of two or more gases into a uniform mixture.

What is fluidity in gases?

Fluidity in gases refers to their ability to flow with air movement due to density.

How do states of matter depend on pressure and temperature?

States of matter change with variations in pressure and temperature, as seen in melting, vaporizing, freezing, and condensation.

What is a physical change?

A physical change does not affect the chemical composition of a substance.

Give an example of a chemical change.

Burning a fuel, which produces a new substance with a different chemical composition.

What is a molecule?

A molecule is the smallest particle of a substance made up of atoms.

How does molecular theory relate to energy?

Molecular theory helps explain heat energy, electrical energy, and changes of state.

What is the smallest form of matter?

An atom is the smallest form of matter.

What composes the nucleus of an atom?

The nucleus contains protons and neutrons.

What is an element?

An element is composed of only one kind of atom and cannot be reduced any further.

How are metals different from nonmetals?

Metals are generally good conductors of heat and electricity, while nonmetals are not.

Define a compound.

A compound is made up of molecules or atoms that are chemically joined together.

What is a mixture?

A mixture is a combination of different molecules that are not chemically combined.

What is a solution?

A solution is formed when one substance is dissolved by another.

What is the solute in a solution?

The solute is the substance being dissolved in the solution.

How does adhesion affect capillary action?

If adhesive forces are greater than cohesive forces, the liquid will rise in the tube.

What creates surface tension in liquids?

Greater attraction among liquid molecules than the air above creates surface tension.

What is specific gravity?

Specific gravity is the number of times a substance is heavier or lighter than an equal volume of water or air.

How do you calculate density?

Density is calculated as mass per unit volume.

What happens to substances when heated?

Substances expand when heated; volume increases while density decreases.

What unique behavior does water exhibit between 0°C and 4°C?

Water becomes more dense when heated from 0°C to 4°C.

What happens to water when it freezes?

Water expands about 7.5% when it freezes.

How does specific gravity relate to density?

Specific gravity can be used to convert to density by multiplying by the density of water or air.

What is the density of water in lbs/ft³?

The density of water is approximately 62.4 lbs/ft³.

If mercury has a specific gravity of 13.6, what is its density?

The density of mercury would be approximately 848.64 lb/ft³.

Define cohesion with an example.

Cohesion is the attraction between the same molecules, as seen in mercury not wetting a vessel surface.

What is the meniscus in liquids?

The meniscus is the upward or downward curve of liquid in a vessel, shaped by adhesion and cohesion.

Explain what happens when the opening in tubes is smaller for liquid that exhibits capillarity.

A smaller opening leads to more rising or falling action due to stronger adhesive forces.

Why is soldering effective in tight joints?

Soldering is effective because the gap is very tight, enhancing capillary action.

2 factors that affect state of matter?

Temperature and pressure

Characteristics of the 3 states of matter?

Solid: definite shape, mass, volume

Liquid: definite mass, volume. Indefinite shape

Gas: definite mass. Indefinite volume and shape

Soft solder, and air→ mixture or compound?

Mixture

Oxygen, hydrogen, copper, carbon→ mixture, compound, element, molecule?

Elements

Natural gas, water, carbon monoxide, rust → mixture or compound?

Compound

2 things you can do to aid soldering capillary action?

-Ensure tight fit

-Use flux to promote wetting action

Densities of Air imperial and metric:

• Imperial: 0.076 lbs/ft3

• Metric: 1.29 kg/m3

• You cannot just memorize the imperial and convert the lbs to kg. It is a different calculation.

• Specific gravity and relative density are the same thing

Density of Water imperial and metric:

• Imperial: 62.4 lb/ft3

• Metric: 1000 kg/m3

• Water is most dense at 4 Deg C.

Weight of Water imperial and metric:

• Imperial: 10lb/gal, US version: 8.33 lbs/USGAL

• Metric: 1 kg/L

Common SG of Gases:

Air: 1

• Methane:

• Propane:

• Butane:

• H2S:

• Oxygen:

• Nitrogen:

• Air: 1

• Methane: 0.6

• Propane: 1.5

• Butane: 2

• H2S: 1.2

• Oxygen: 1.1

• Nitrogen: 0.97

Common SG of Liquids/Solids:
Water: 1

• Ice:

• Methane:

• Propane:

• Butane:

• Copper:

• Cast Iron:

• Mercury:

• Lead:

• Steel:

How much does water expand when changing to ice?

7.5%

Water at 4 Deg C is?

Most Dense point of water

Matter is?

Anything that has mass and occupies space

Element vs Compound?

Element : contains only molecules of that element

Compound: chemical union of different molecules

Compound vs Mixture?

Mixture: contains different molecules but not chemically united

Compound: chemical union of different molecules

Mercury in glass tube - adhesive or cohesive classification?

cohesive

Define surface tension.

Molecular attraction of molecules to eachother at surface of liquid

How does a pressure cooker reduce cook times?

Increased pressure and increased temperature

Solder flowing into a joint is a result of? (2 things)

Adhesion and capillary action

Correct simple definition relative density (SG) for liquids and solids?

Mass of substance compared to the mass of an equal volume of water.

An object has mass of 1875 kg, relative density of 1.5, what is the volume?

Volume = mass / density

1m3 = 1000kg water

1875kg / (1000 kg ×1.5 SG) = 1.25 m3

Mass of 10 USGallons of a liquid with relative density of 1.85?

1 usgal = 8.33 lbs water

8.33 lbs x 10 usgal x 1.85 SG = 154.105 lbs.

Mass of water in a tank with a volume of 11.25 ft3?

11.25 ft3 × 62.4 lbs/ft3 = 702 lbs

Liquids that are cohesive create what type of meniscus?

Convex Mensicus. If not cohesive it would be concave.

What is the mass of 1 in3 of water?

62.4 / 12³ = 0.0361 lbs/in3 so 0.0361 lbs

A solid object has a density of 0.244 lbs/in3, what is relative density?

Solids and liquids are always referenced to water!
first do lbs/ft3 to lbs/in3 → 62.4 lbs / 12³ = 0.0361.
0.244 lbs/in3 / 0.0361lbs/in3 = 6.76 SG

SG of a gas with a density of 1.52 kg/m3?

Divide it by the density of air in metric. (1.29 kg/m3)

1.52 / 1.29 kg/m3 = 1.31 SG