Unit 1 Part 1 Flashcards

1
Q

What is the difference between a physical and chemical change?

A

Physical changes are usually reversible (eg: changes of state).

Chemical changes are usually permanent and always produce a new substance.

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2
Q

Define Exothermic

Define Endothermic

A

Exothermic : Releases heat

Endothermic : Takes in heat

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3
Q

Define a catalyst

A

Catalysts are used to speed up a reaction rate which can be recovered unchanged.

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4
Q

Equation to measure rate of reaction

A

change in property
——————————
change in time

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5
Q

Describe the structure of an atom

A

Nucleus contains protons and neutrons. Electrons orbit around in different energy levels.

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6
Q

What are ions?

A

A changed particle

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7
Q

How are ions formed?

A

When an atom gains or loses electrons

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8
Q

Why do atoms for ions?

A

to achieve a stable electron arrangement

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9
Q

What can be said of the balance of protons and electrons in an atom compared to an ion?

A

atoms have equal amounts of protons to electrons

ions don’t have an equal amount for protons and electrons

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10
Q

Why are atoms neutral?

A

the protons and electrons cancel out

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11
Q

What’s the electron arrangement of any atom?

A

2
8
8
18

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12
Q

In Nuclide notation where does the mass number go?

A

Top left

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13
Q

How do you find the mass number?

A

Number of protons + number of electrons

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14
Q

In nuclide notation where do you find the atomic number?

A

Bottom left

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15
Q

How do you find the atomic number?

A

Number of protons

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16
Q

What are isotopes?

A

Atoms of the same element which have different mass numbers

Isotopes have different numbers of neutrons

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17
Q

On the periodic table, where do you find the atomic number

A

Above the letter

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18
Q

What’s the valency equal to?

A

valency = charge

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19
Q

What is RAM

A

Relative atomic mass

20
Q

Define RAM

A

the average mass of the isotopes present taking into account their relative proportions.

21
Q

What’s the most common isotope

A

Carbon

22
Q

Which atom is the atom against which all mass of all other atoms are compared to?

A

Carbon

6P , 6N, 6E

23
Q

How do you calculate RAM?

A

total mass of all atoms present
————————————————
number of atoms present

(% abundance X mass of isotope) + (same )
————————
100

24
Q

What is covalent bonding?

A

a chemical bond that involves the sharing of electron pairs between atoms

25
Q

What’s it called when’s. covalent bond shares 2 pairs of electrons?

A

Double covalent bond

26
Q

What are the different structures?

A

Linear
Angular
Pyramidal
Tetrahedral

27
Q

What are discrete covalent molecules?

A

small and contain the number of atoms indicated in the formula, eg: CO2 has 3 atoms

28
Q

What is a covalent network?

A

giant structure with a huge number of atoms

29
Q

What is an intermolecular force?

A

weak forces of attraction

30
Q

Define ionic bond

A

when one element donates an electron (or electrons) to another so that both elements will have a full outer shell.

a metal transfers an electron to a non metal

31
Q

Define metallic bonding

A

Metallic bond, force that holds atoms together in a metallic substance.

32
Q

How are atoms of a metallic bond arranged?

A

Metals consist of giant structures of atoms arranged in a regular pattern. The electrons from the outer shells of the metal atoms are delocalised , and are free to move through the whole structure.

33
Q

What’s special about electrons in metals?

A

They can move freely

34
Q

Covalent networks have a

_____ melting point

A

high

35
Q

What’s broken in covalent networks?

A

strong covalent bonds

36
Q

Do covalent bonds conduct electricity?

A

No, except graphite

37
Q

Covalent molecules have a ____ melting point?

A

low

38
Q

What’s broken in covalent molecules?

A

weak intermolecular forces

39
Q

Are covalent networks soluble in water?

A

no insoluble

40
Q

Do covalent molecules conduct electricity?

A

doesn’t conduct electricity in any state

41
Q

Are covalent molecules soluble in water?

A

they’re more likely to be soluble

42
Q

Ionic lattices have a ____ melting point

A

high

43
Q

What’s broken in an ionic lattice?

A

strong ionic bonds

44
Q

Do ionic lattices conduct electricity

A

only melted or in solution

45
Q

Are ionic lattices soluble in water?

A

more likely to be soluble