chemistry - ions

Question 1

What is independent variable?

Answer 1

The variable for which values are changed.

Question 2

What does the limitation of the simple particle model include?

Answer 2

In the model there are no forces so all particles are shown as spheres and the spheres are solid.

Question 3

What is the dependent variable?

Answer 3

The variable for which the value is measured.

Question 4

What are control variable?

Answer 4

The ones which must be kept the same (constant).

Question 5

What are the three states of matter?

Answer 5

Solid, Liquid and Gas.

Question 6

The stronger the forces between the particles…

Answer 6

…the higher the melting and boiling point of the substance.

Question 7

What are the three states of matter shown as in chemical equations?

Answer 7

(s) (l) (g) with (aq) for aqueous solutions.

Question 8

Why do metal atoms lose electrons?

Answer 8

To become positively charged ions.

Question 9

Why do non-metal atoms gain electrons?

Answer 9

To become negatively charged ions.

Question 10

What is an ionic compound?

Answer 10

A giant structure of ions.

Question 11

How are ionic compounds held together?

Answer 11

By strong electrostatic forces of attraction between oppositely charges ions.

Question 12

What happens when atoms share pairs of electrons?

Answer 12

They form covalent bonds. These bonds between atoms are strong.

Question 13

What have very large molecules?

Answer 13

Some covalently bonded substances such as polymers.

Question 14

What have giant covalent structures?

Answer 14

Some covalently bonded substances such as chemical and silicon dioxide.

Question 15

What represents a single bond?

Answer 15

A single line.

Question 16

What do metals consist of?

Answer 16

Giant structure of atoms arranged in a regular pattern.

Question 17

What are the electrons in the outer shell of metal atoms?

Answer 17

Delocalised so they are free to move through the whole structure. The sharing of delocalised electrons gives rise to strong metallic bonds.

Question 18

What is the melting and boiling point of ionic compounds? And Why?

Answer 18

High because of the large amounts of energy needed to break the many strong bonds.

Question 19

What happens when ionic compounds are melted or dissolved in water?

Answer 19

They conduct electricity because the ions delocalised and so charge can flow.

Question 20

What substance consist of small molecules?

Answer 20

Usually gases or liquids that have relatively low melting and boiling points.

Question 21

What happens with the intermolecular forces between small molecules?

Answer 21

They increase with the size of the molecules so larger molecules have higher melting and boiling points.

Question 22

How are the atoms in the polymer molecules linked?

Answer 22

To other atoms by strong covalent bonds.

Question 23

How strong are the intermolecular forces between polymer molecules?

Answer 23

Relatively strong so these substances are solids at room temperature.

Question 24

What substances consists of giant covalent structures?

Answer 24

Solids with very high melting points which its atoms are all linked by strong covalent bonds.

Question 25

What are examples of giant covalent structures?

Answer 25

Diamond and Graphite (forms of carbon) and silicon dioxide (silica).

Question 26

What is a metal’s melting and boiling point? And why?

Answer 26

High because they have giant structures of atoms with strong metallic bonding.

Question 27

How are atoms arranged in pure metals?

Answer 27

Layers which allow metals to be bent and shaped.

Question 28

Why are metals good conductors of electricity?

Answer 28

The delocalised electrons in metal carry electrical charge through the metal.

Question 29

When in graphite, each carbon atom forms three covalent bonds with three other carbon, what does this form?

Answer 29

Layers of hexagonal rings which have no covalent bonds between them.

Question 30

What is graphene?

Answer 30

A single layer of graphite and has properties that make it useful in electronics and composites.

Question 31

What are fullerenes?

Answer 31

Molecules of carbon with hollow shapes.

Question 32

What is the structure of fullerenes?

Answer 32

Hexagonal rings of carbon atoms which may contain rings with five or seven carbon atoms.

Question 33

What are carbon nanotubes?

Answer 33

Cylindrical fullerenes.

Question 34

What are carbon nanotubes’ properties?

Answer 34

High length to diameter ratios. Useful for nanotechnology, electronics and materials.

Question 35

What’s are precise measurements.

Answer 35

Ones where there is little spread about the mean value.

Question 36

What’s are accurate measurements?

Answer 36

Close to the true value.

Question 37

What do valid experiments answer?

Answer 37

The question being asked.

Question 38

When is measurement repeatable?

Answer 38

If the experiment is carried out by the same person using the same method and has the same results.

Question 39

What does reproducible mean?

Answer 39

When the same experiment is carried out by a different person or group and you get the same results.