Download I Examen I Trim Science

Resumen Science
1- Define Chemistry and Matter
Chemistry: science concerned with the composition, structure and properties of matter, as well
as the changes it undergoes during chemical reaction. Chemistry is a central science.
Matter: is anything that has mass and volume (takes up space).
 Everything in the universe that you can see is made up of some type of matter.
 The Difference between Mass and Weight: Weight is the measure of the gravitational
force exerted on an object. The more mass an object has, the greater the gravitational force
on the object and the greater the object’s weight.
2- Describe the two types of research: basic and applied and examples of them.
Research:
 Basic: help us with the understanding of how natural world operates. Ex. Rain, plants
growing, volcanoes.
 Applied: focuses on developing these applications. Ex. Shampoo, Tosty food, Panadol.
3- Identify the properties used to describe matter: physical and chemical properties.
Properties of matter: describe characteristics and behavior of matter.
Physical properties: can be observed or measures without changing matter’s identity.
Chemical properties: describe matter on its ability to change into new matter that has
different properties
Physical properties of matter:
1. Density: amount of matter in a given space or volume. Tells if the substance will float
or sink
Substances
Density (g/mL)
Helium (gas)
0.0001663
Oxygen (gas)
0.001331
Water (liquid)
1.00
Pyrite (solid)
5.02
Mercury (liquid)
13.55
2. Thermal conductivity: substance transfer heat.
Ex. Metal is a good conductor, and plastic is a poor conductor
3. State: physical from into which a substance exist.
Ex. Gas, liquid, solid, plasma
4. Solubility: ability of a substance to dissolve into another substance.
Ex. Tang in water
5. Ductility: ability of a substance to pure into a wire.
Ex. Cooper
6. Malleability: is the ability of a substance to be rolled or pounded into thin sheets
Ex. Aluminum
7. Elasticity: ability to change form when a force is applied and return to its original way
when a force is removed.
Ex. Rubber
8. Persistence: resistance of objects to break or change form when hit.
Ex. Iron to make furniture
9. Fragility: ability to an object to break caused by preassure or other force.
Ex. Crystals
10. Hardness: resistance in a mineral of been scratched by other mineral
Ex. Diamond
11. Electrical conductivity: ability of a substance to transfer electric current.
Ex. Metals
12. Fusion Point: temperature needed in a substance to change from solid to liquid.
Ex. Gold 1063˚C water 0˚C
13. Boiling point: temperature needed in which a liquid changes into a gas.
Ex. Water 100˚C
14. Texture: way into which particles are placed in space in an object. Perceived by touch
15. Color: property perceived by the due to the effect of light reflected by objects.
16. Taste: ability or quality in a substance perceived by the tongue.
Ex. Bitter, sweet
17. Odor: produced by the emanation of objects perceived by smell.
Chemical properties of matter:
1. Flammability: ability of a substance to burn.
Ex. Wood, fuel (ash, smoke has no flammability)
2. Reactivity: ability to combine and form new substances.
Ex. Iron reacts with oxygen and forms rust
3. Oxidation: ability to react with oxygen and form rust.
Ex. Iron
4. Toxicity: substances with the ability to react and produce poison or other substances that
causes different damages on living organisms
Ex. Fungicides
5. Fermentation and decomposition: ability in natural substances to change due to
different bacterias or fungi chemical process of substances with high levels or glucose
that changes to alcohol.
Ex. Grapes – wine
6. Photosynthesis: ability in matter that changes carbon dioxide and water into oxygen and
glucose.
Ex. Plants and algae.
7. Digestion: ability of braking down substances into small pieces or particles.
4. Express mass and volume with the correct SI units.
Mass: Amount of matter in an object.
Measured by g, kg
Volume: amount of space taken up or occupied by an object.
Measured by cm3, m3, mL,L
Weight: is a measure of gravitational force
Measured by: unit of force, the newton (N).
5. Solve for density and volume for any given word problem, making sure to follow the
problem solving steps and answering with the appropriate units. *Formulas must be
memorized
Density:
Formula: d= m/v
Units: g/mL , kg/L, g/cm3, kg/m3
Steps to find D:
1. Measure mass
2. Measure volume
3. Use the formula
Volume:
Formula: length * weight * height
Units: cm3, m3, mL,L
6. Describe what physical and chemical changes are and provide examples.
Physical changes: any change that affects the physical properties of a substance.
Anything that undergoes through a change, but without a change in its identity. DO NOT
change the identity of matter.
Ex. Change of state, heating water, freezing water, a piece of silver pounded into a heartshaped charm.
Reversibility:
- Can be reversed
- Easy to undo
Chemical changes: causes a substance to change a new substance. Sometimes there’s a
change in the way atoms are chemically bonded.
Ex. Flammability – burning
* Chemical changes and chemical properties are not the same. Chemical properties
describe what chemical change can happen to the substance. *
Chemical bond: force of attraction between two atoms that hold them together, H2O.
Any change in a substance that involves a rearrangement of the way atoms are bonded is
a chemical change. Material undergoing a chemical change is said to be reacting.
Chemical reaction: new materials are formed by a change in the way atoms are bonded
together. (Chemical changes = chemical reaction)
Ex.
-Process when using a battery
-When your body is in digestion
-Soured milk
-Moist in a sculpture
Sings of chemical changes:
- Change in color
- Change in texture
- Producing/ decreasing temperature
- Formation mew substance
Chemical Changes:
 Substance’s identity changes
 Can’t be reverser, only by other chemical changes.
Characteristics
Composition
Reversing Changes
Identity
Properties
Physical Change
Do not change
Can do it
Stays the same
Stays the same
Chemical Change
changes
Can’t do it just with a chemical change
Changes into new substances
Changes into new chemical and physical properties
7. Analyze the states of matter and give examples of them and
8. Explain how particles behave in each of the states of matter.
The states of matter: are the physical forms in which a substance can exist. The three
most familiar states of matter are solid, liquid, plasma and gas.
Matter is made up of tiny particles called atoms and molecules. These particles are
always in motion and are always bumping into one another.
The way the particles interact with each other helps determine the state of the matter.
Solids
 A solid is the state of matter that has a definite shape and volume.
 The particles in a solid do not move fast enough to overcome the attraction between
them.
 Each particle vibrates in place and is locked in place by the particles around it.
2 types of solids:
 Crystalline solids: have a very orderly, three-dimensional arrangement of particles.
Iron, diamond, and ice are crystalline solids.
 Amorphous solids: are made of particles that do not have a special arrangement.
Glass, rubber, and wax are amorphous solids.
Liquids:
 Liquid is the state of matter that has a definite volume and but takes the shape of its
container.
 The particles of a liquid move fast enough to overcome some of the attraction
between them.
 The particles in a liquid slide past each other.
Liquids Have Unique Characteristics:
 Surface tension is a force that acts on the particles at the surface of a liquid.
 Viscosity is a liquid’s resistance to flow.
Gases:
 Gas is the state of matter that has no definite shape or volume.
 The particles of a gas move quickly and can break away completely from one
another.
 The amount of empty space between gas particles can change.
9.Explain what affects how a gas behaves
 Temperature
Temperature is a measure of how fast the particles in an object are moving. The faster the
particles are moving, the more energy they have.
 Volume
Volume is the amount of space that an object takes up. Because gas particles spread out,
the volume of any gas depends on the container that the gas is in.
 Pressure:
The amount of force exerted on a given area of surface is called pressure. You can think
of pressure as the number of times the particles of a gas hit the inside of their container.
10. Analyze the gas laws

Boyle’s Law
Boyle’s law states that for a fixed amount of gas at a constant temperature, the volume of
the gas is inversely related to pressure.

Charles’s Law
Charles’s law states that for a fixed amount of gas at a constant pressure, the volume of
the gas changes in the same way that the temperature of the gas changes.