Gr 9 Chemistry

Question 1

What is matter?

Answer 1

Anything that has mass and takes up space (volume)

Matter is composed of particles.

Question 2

What is the process of changing from solid to liquid called?

Answer 2

Melting

Example: Ice to water.

Question 3

What is the process of changing from liquid to solid called?

Answer 3

Freezing

Example: Water to ice.

Question 4

What is the process of changing from liquid to gas called?

Answer 4

Evaporation

Example: Water to steam.

Question 5

What is the process of changing from gas to liquid called?

Answer 5

Condensation

Example: Steam to water.

Question 6

What is the process of changing from solid to gas called?

Answer 6

Sublimation

Example: Dry ice to gas.

Question 7

What is the process of changing from gas to solid called?

Answer 7

Deposition

Example: Water vapor to frost.

Question 8

What are physical properties?

Answer 8

Properties that can be observed without changing the chemical composition of a substance.

Physical properties can be qualitative or quantitative.

Question 9

What are qualitative properties?

Answer 9

Observations using the senses.

Examples include luster, clarity, brittleness, viscosity, hardness, malleability, ductility, and electrical conductivity.

Question 10

Define luster.

Answer 10

Shininess or dullness.

Luster is a qualitative property of matter.

Question 11

What does clarity refer to?

Answer 11

Transparent, translucent, or opaque.

Clarity is a qualitative property of matter.

Question 12

What is brittleness?

Answer 12

How easily a substance breaks.

Brittleness is a qualitative property of matter.

Question 13

Define viscosity.

Answer 13

Flow rate.

Viscosity is a qualitative property of matter.

Question 14

What does hardness measure?

Answer 14

Resistance to scratching or breaking.

Hardness is a qualitative property of matter.

Question 15

What is malleability?

Answer 15

Ability to be molded or hammered.

Malleability is a qualitative property of matter.

Question 16

Define ductility.

Answer 16

Ability to be stretched into wires.

Ductility is a qualitative property of matter.

Question 17

What is electrical conductivity?

Answer 17

Ability to conduct electricity.

Electrical conductivity is a qualitative property of matter.

Question 18

What are quantitative properties?

Answer 18

Measurements of a substance.

Examples include volume, mass, and density.

Question 19

What units are used for volume?

Answer 19

cm³ or mL.

Volume is a quantitative property.

Question 20

What units are used for mass?

Answer 20

grams or kilograms.

Mass is a quantitative property.

Question 21

How is density calculated?

Answer 21

Density = Mass / Volume (units: g/cm³ or g/mL).

Density is a quantitative property.

Question 22

What are chemical properties?

Answer 22

Chemical changes that are specific to a substance and result in the formation of new substances.

Examples include reactivity with oxygen, flammability, or formation of a precipitate.

Question 23

Define physical change.

Answer 23

A change in the physical properties of a substance without altering its chemical structure.

Examples include melting ice, boiling water, and dissolving sugar.

Question 24

List key traits of a physical change.

Answer 24

Reversible, no new substances formed.

Physical changes do not alter the chemical identity of the substance.

Question 25

What is a chemical change?

Answer 25

A transformation that produces one or more new substances. ## Footnote Chemical changes involve alterations at the molecular level.

Question 26

What are signs of a chemical change?

Answer 26

* Change in color * Formation of bubbles (gas) * Formation of a precipitate (solid) * Change in smell * Release of light, heat, or sound ## Footnote These signs indicate that a chemical reaction has occurred.

Question 27

List key traits of a chemical change.

Answer 27

Irreversible, new substances formed. ## Footnote Chemical changes result in the formation of substances with different properties.

Question 28

What is the Particle Theory of Matter?

Answer 28

All matter is made of particles with spaces between them, which vary by state.

Question 29

What are the spaces between particles in solids, liquids, and gases?

Answer 29

* Solid: Small spaces * Liquid: Medium spaces * Gas: Large spaces

Question 30

How do particles of different substances compare?

Answer 30

Particles of different substances are different.

Question 31

What is the motion of particles?

Answer 31

Particles are in constant random motion.

Question 32

How does temperature affect particle motion?

Answer 32

At higher temperatures, particles move faster; at lower temperatures, they move slower.

Question 33

What is the relationship between particles in terms of attraction?

Answer 33

Particles are attracted to each other.

Question 34

What happens to particle energy and spacing when heat is added?

Answer 34

Adding heat increases particle energy, motion, and spacing.

Question 35

What happens to particle energy and spacing when cooling occurs?

Answer 35

Cooling decreases particle energy and spacing.

Question 36

What is the formula for density?

Answer 36

Density = Mass / Volume

Question 37

How can mass be calculated using density and volume?

Answer 37

Mass = Density * Volume

Question 38

How can volume be calculated using mass and density?

Answer 38

Volume = Mass / Density

Question 39

What are the units for density in solids and liquids?

Answer 39

* g/cm³ (solids) * g/mL (liquids) * kg/m³ (general)

Question 40

What is the conversion factor between g/cm³ and kg/m³?

Answer 40

1 g/cm³ = 1000 kg/m³

Question 41

What is a unique property of water?

Answer 41

Solid water (ice) is less dense than liquid water.

Question 42

Why does ice float on water?

Answer 42

Due to its crystal lattice structure, allowing ice to be less dense than liquid water.

Question 43

Fill in the blank: Density = _______.

Answer 43

Mass / Volume

Question 44

True or False: Particles in a gas have small spaces between them.

Answer 44

False

Question 45

What are the two types of pure substances?

Answer 45

Elements and Compounds ## Footnote Elements cannot be broken down, while compounds are made of two or more elements chemically bonded.

Question 46

Give an example of a compound.

Answer 46

Water (H2O) ## Footnote Other examples include Salt (NaCl).

Question 47

What characterizes a homogeneous mixture?

Answer 47

Uniform appearance, particles not visible ## Footnote An example is saltwater.

Question 48

What is a heterogeneous mixture?

Answer 48

Particles are visible ## Footnote An example is milk and granola.

Question 49

What do groups in the periodic table indicate?

Answer 49

Similar chemical properties ## Footnote For example, reactivity among elements.

Question 50

What do periods in the periodic table show?

Answer 50

The number of electron shells ## Footnote Each row represents a different energy level.

Question 51

List the classifications of elements.

Answer 51

* Metals * Non-Metals * Metalloids ## Footnote Metals are on the left, non-metals on the right, and metalloids have properties of both.

Question 52

What are the characteristics of Group 1 elements?

Answer 52

* Shiny * Low density * Most reactive metals ## Footnote These are known as Alkali Metals.

Question 53

How do Group 2 elements differ from Group 1?

Answer 53

Shiny and reactive, but less so than Group 1 ## Footnote These are known as Alkaline Earth Metals.

Question 54

What are Transition Metals known for?

Answer 54

Transitioning (changing), don’t follow all the rules ## Footnote They are found in Groups 3-12.

Question 55

Describe Group 17 elements.

Answer 55

Most reactive non-metals, often poisonous ## Footnote These are known as Halogens.

Question 56

What is unique about Group 18 elements?

Answer 56

Stable and unreactive ## Footnote These are known as Noble Gases.

Question 57

What is the smallest unit of an element?

Answer 57

Atom ## Footnote Atoms make up all matter.

Question 58

Define a molecule.

Answer 58

Two or more atoms chemically combined ## Footnote Molecules can consist of the same or different elements.

Question 59

What are diatomic elements?

Answer 59

Elements that naturally exist as two atoms ## Footnote Examples include H2 and O2.

Question 60

What does a Bohr-Rutherford diagram illustrate?

Answer 60

The structure of an atom ## Footnote It shows the number of neutrons and protons in the nucleus and the number of electrons in each orbital.

Question 61

What is represented in the nucleus of a Bohr-Rutherford diagram?

Answer 61

The number of protons and neutrons ## Footnote It is represented as a circle with these quantities indicated inside.

Question 62

How are electrons represented in a Bohr-Rutherford diagram?

Answer 62

As dots on circles (shells) around the nucleus ## Footnote Each circle represents an orbital.

Question 63

How many electrons fit in the first shell?

Answer 63

2 electrons ## Footnote The first shell can hold a maximum of 2 electrons.

Question 64

How many electrons fit in the second and third shells?

Answer 64

8 electrons each ## Footnote The second and third shells can hold 8 electrons.

Question 65

How many electrons fit in the fourth shell?

Answer 65

2 electrons ## Footnote The fourth shell has a lower capacity compared to the second and third shells.

Question 66

Fill in the blank: A Bohr-Rutherford diagram shows the number of _______ and protons in the nucleus.

Answer 66

neutrons

Question 67

True or False: Non-metals are typically good conductors of electricity.

Answer 67

False ## Footnote Non-metals are generally poor conductors.