Unit 1

Question 1

A heterogeneous mixture

Answer 1

a mixture in which the composition is not uniform throughout the mixture.

Question 2

homogeneous

Answer 2

A homogeneous mixture is a mixture in which the composition is uniform throughout the mixture

Question 3

compound

Answer 3

a compound is a substance made up of two or more different chemical elements combined in a fixed ratio

Question 4

element

Answer 4

a pure substance that cannot be broken down by any physical or chemical means into simpler substances

Question 5

chemistry

Answer 5

in this science we study matter and the changes it undergoes

Question 6

scientific method

Answer 6

the scientific method is simply a systematic approach to solving problems

Question 7

Matter

Answer 7

we define matter as anything that has mass and takes up space

Question 8

matter(atoms)

Answer 8

-atoms are the building blocks of matter
-each element is made of the same kind of atom
-a compound is made of two or more different kinds of elements

Question 9

Classification of matter (particle theory of matter)

Answer 9

-all matter is made up of tiny particles
-each pure substance has its own kind of particle which is different from the particles of other pure substances
-particles attract each other
-particles are always moving
-particles at a higher temperature move faster,on average,than particles at a lower temperature

Question 10

what are the 3 states of matter

Answer 10

gas, liquid, crystalline solid (soild)

Question 11

gas

Answer 11

Total disorder, much empty space ; particles have complete freedom of motion particles far apart

Question 12

liquid

Answer 12

disorder, particles or clusters of particles are free to move relative to each other, particles close together

Question 13

crystalline solid

Answer 13

ordered arrangement; particles are essentailly in fixed positions;particles close together

Question 14

classification of matter

Answer 14

matter can be classified grouped based on different characteristics

Question 15

Element

Answer 15

• pure substance
• cannot be broken down into simpler parts by chemical or physical methods
• eg. helium(He), oxygen(O),hydrogen (H)

Question 16

Compound

Answer 16

• pure substances
• made of two or more different elements that are chemically combined

Question 17

Mixture

Answer 17

• matter that contains **more than one **kind of particle
• eg. salt water=water particles (H2O) + salt ( NaCI) particles
• eg. air+oxygen(02)+ nitrogen(N₂) + carbon dioxide(CO₂) + other gases
• e.g. vinegar = acetic acid (CH3COOH(aq)) +
  water particles (H2O)

Question 18

info about mixtures

Answer 18

mixtures can be homogeneous or heterogeneous.
* A** homogeneous mixture** is one where the
components that make up the mixture are
uniformly distributed throughout the mixture.
* The mixture looks the same throughout.
* Examples: air, blood, saturated sugar water

Question 19

info about mixtures part 2

Answer 19

• A heterogeneous mixture is a mixture where the
  components of the mixture are not uniform or
  have localized regions with different properties.
• The mixture does not look the same throughout.
• Examples: sand, oil and water, granola, pizza
• The components of a mixture are physically
  combined. As a result, a mixture can be separated
  by physical methods.

Question 20

Filtration

Answer 20

In filtration solid
substances are
separated from liquids
and solutions.
eg. a filter separating coffee grounds from the brewed coffee that passes through

Question 21

Distillation

Answer 21

Distillation uses
differences in the
boiling points of
substances to
separate a
homogeneous
mixture into its
components.
eg. an apparatus shows how a liquid with a lower boiling point than other components in a mixture it is vaporized ,condensed and collected in a beaker

Question 22

What are the advantages elements and compounds have on our society

Answer 22

making our lives healthier and safer and enabling us to accomplish
things that were once unimaginable.

Question 23

What are the disadvantages elements and compounds have on our society

Answer 23

negative consequences, such as the
release of pollutants into the environment.
In many cases, humans need to
determine whether the advantages
outweigh the disadvantages.

Question 24

physical property

Answer 24

is a characteristic of a substance that can be
observed and measured without changing the identity of the substance.
The physical properties of
materials play a significant role
in determining practical uses for
these substances.

Question 25

Qualitative physical properties

Answer 25

can be observed and described without detailed measurement.

Question 26

Qualitative properties are:

Answer 26

colour, odour,state,texture, lustre and malleability

Question 27

Quantitative physical properties

Answer 27

are properties that can be measured and assigned a particular value

Question 28

Quanititative physical properties are:

Answer 28

viscosity, melting point,boiling point, solubility, hardness, conductivity and density

Question 29

What are the 2 types of properties

Answer 29

Intensive and Extensive Properties

Question 30

Intensive properties

Answer 30

Are independent of the amount of the substance that is present. eg.Density, boiling point, color, etc.

Question 31

Extensive properties

Answer 31

Depend upon the amount of the substance present. eg. mass, volume, energy,ect.

Question 32

states of matter

Answer 32

The specific temperature at which an element or compound changes state is a characteristic physical property illustrated by the diagram below.

Question 33

What are the changes of state

Answer 33

melting,solidification,evaporation,condensation,sublimation and deposition

Question 34

melting

Answer 34

changing from a solid to a liquid (ice turning to water)

Question 35

solidification

Answer 35

changing from a liquid to a solid (water freezing)

Question 36

evaporation

Answer 36

changing from a liquid to a gas (a puddle disappears on a hot day)

Question 37

condensation

Answer 37

changing from a gas to a liquid (drops of water forming on a cold glass in the summer)

Question 38

sublimation

Answer 38

changing from a solid to a gas (dry ice disappearing)

Question 39

deposition

Answer 39

changing from a gas to a solid (the formation of frost)

Question 40

solubility

Answer 40

is the maximum quantity of a substance (solute) that can dissolve in a given amount of solvent at a particular temperature and pressure. Solubility is measured in units of mass of solute per mass of solvent or mass of solute per volume of solvent. | Solutions with water as the solvent are called **aqueous solutions.**

Question 41

solubility and the environment

Answer 41

*Solubility in fat is an especially important property for some chemicals. For this reason, toxic substances such as DDT can build up in the fat of animals. This **bioaccumulation** leads to the **biomagnification** of the toxin at higher levels of the food chain.

Question 42

Hardness

Answer 42

The hardness of a substance refers to its ability to be scratched. Hardness is measured using Moh’s scale (a scale from 1 to 10, with 10 being hardest). Harder substances will scratch softer materials that are lower on the scale. At 10 on Moh’s scale, diamond is the hardest natural material on Earth. Drill bits use diamonds to cut through other slightly less hard substances.

Question 43

Density

Answer 43

is the ratio of the mass of a substance to the volume it occupies. The density of a substance can be calculated by using the following formula: D= m / v

Question 44

Density of a material

Answer 44

The density of a material determines if it will float on top of another substance. Less dense substances, such as the bunker oil shown in the picture on the left, float on the more dense salt water. An understanding of the densities of substances can be used when attempting to separate them.

Question 45

water's unique physical properties

Answer 45

* is called the “universal solvent” * is more dense as a liquid than as a solid (ice floats on water) * is the only natural substance that exists as a solid, liquid, and gas on Earth * can absorb a lot of heat before it gets hot. It has a high specific heat capacity.