Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chem Combined Higher > FlashCards (Save my Exams) > Flashcards

FlashCards (Save my Exams)

1
Q

What are coarse particles?

A

Coarse particles (PM10) have diameters between 1 x 10-5 m and 2.5 x 10-6 m. They are often referred to as dust.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a conductor?

A

A material which contains charged particles that are free to move to carry electrical or thermal energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is a covalent bond?

A

A shared pair of electrons between two non-metals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is diamond?

A

A giant covalent structure made up of carbon atoms, each of which forms four covalent bonds with four other carbon atoms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are electrostatic forces?

A

The strong forces of attraction between oppositely charged ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an empirical formula?

A

The smallest whole number ratio of atoms of each element in a compound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are fine particles?

A

Fine particles (PM2.5) have diameters between 100 and 2500 nm (1 x 10-7 m and 2.5 x 10-6 m).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are fullerenes?

A

Molecules of carbon atoms with hollow shapes, based on hexagonal rings of carbon atoms, but may also contain rings with five or seven carbon atoms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is gas?

A

The state of matter where the particles have the most energy, are relatively spread out, and move randomly in all directions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is graphene?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is graphite?

A

A giant covalent structure made up of carbon atoms, each of which forms three covalent bonds with three other carbon atoms, forming layers of hexagonal rings with no covalent bonds between the layers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is an ion?

A

An atom or molecule with an electric charge due to the loss or gain of electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is an ionic bond?

A

A bond formed when a metal atom loses electron(s) to form a positively charged ion and a non-metal gains these electron(s) to form a negatively charged ion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is an ionic compound?

A

A chemical compound formed of ions, held together by strong electrostatic forces.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are intermolecular forces?

A

The forces which exist between molecules, impacting physical properties like boiling/melting point.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a lattice?

A

A repeating regular arrangement of atoms/ions/molecules, occurring in crystal structures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is liquid?

A

The state of matter where the particles are arranged randomly and close together, able to move past each other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a metallic bond?

A

The bonds present in metals between the positive metal ions and negatively charged electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are metals?

A

Elements that react to form positive ions, found to the left and towards the bottom of the periodic table.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a molecular formula?

A

The actual ratio of atoms of each element present in a compound.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are nanoparticles?

A

Nanoparticles have diameters between 1 nm to 100 nm in size and can exhibit properties different from those of the same material in bulk.

22
Q

What is nanoscience?

A

Nanoscience refers to structures that are 1–100 nm in size, of the order of a few hundred atoms.

23
Q

What are non-metals?

A

Elements that react to form negative ions, found towards the right and top of the periodic table.

24
Q

What is particle theory?

A

The theory which models the three states of matter by representing the particles as small solid spheres, explaining melting, boiling, freezing, and condensing.

25
What are polymers?
Large long-chain molecules made up of lots of small monomers joined together by covalent bonds.
26
What is a repeat unit?
The part of a polymer whose repetition would produce the complete polymer chain.
27
What is solid?
The state of matter where the particles hold a regular arrangement and have the least amount of energy.
28
What are state symbols?
The symbols used in chemical equations to denote the states of the chemicals reacting: (s) - solid, (l) - liquid, (g) - gas, (aq) - aqueous solution.
29
30
What is ionic bonding?
Ionic bonding is the electrostatic attraction between positive and negative ions.
31
How are ionic compounds held together?
They are held together in a giant lattice. It’s a regular structure that extends in all directions in a substance. Electrostatic attraction between positive and negative ions holds the structure together.
32
State properties of ionic substances
High melting and boiling point (strong electrostatic forces between oppositely charged ions). Do not conduct electricity when solid (ions in fixed positions). Conduct when molten or dissolved in water - ions are free to move.
33
Give 5 examples of positive ions and 5 examples of negative ions.
E.g. Positive: Na+, Mg2+, Al3+, Ca2+, Rb+. E.g. Negative: Cl−, Br−, SO4 2−, NO3 −, OH− (chloride, bromide, sulfate, nitrate, hydroxide).
34
What is important when working out a formula of an ionic compound?
Ionic compounds are electrically neutral, i.e. positive and negative charges balance each other.
35
How are ionic compounds formed? Explain in terms of MgO case.
Reaction of a metal with a non-metal. Electron transfer occurs - metal gives away its outer shell electrons to non-metal. Mg is in Group II, so has 2 available outer shell electrons. O is in Group VI, so can accept 2 electrons to get a full outer shell configuration. Mg becomes Mg2+ and O becomes O2− (oxide).
36
What is a covalent bond?
Covalent bond is a shared pair of electrons between two atoms.
37
Describe the structure and properties of simple molecular covalent substances.
Do not conduct electricity (no ions). Small molecules. Weak intermolecular forces, therefore: Low melting and boiling points.
38
How do intermolecular forces change as the mass/size of the molecule increases?
They increase. That causes melting/boiling points to increase as well (more energy needed to overcome these forces).
39
What are polymers? What are thermosoftening polymers?
Polymers are very large molecules (>100s, 1000s of atoms) with atoms linked by covalent bonds. Thermosoftening polymers - special type of polymers; they melt/soften when heated. There are no bonds between polymer chains. Weak intermolecular forces ensure that the structure is solid at room temperature. These forces are overcome with heating - polymer melts.
40
What are giant covalent substances? Give examples.
Solids, atoms covalently bonded together in a giant lattice. High melting/boiling points – strong covalent bonds. Mostly don’t conduct electricity (no delocalised e−). Examples: Diamond, graphite, silicon dioxide.
41
Describe and explain the properties of allotropes of carbon.
Diamond – four, strong covalent bonds for each carbon atom – very hard (Strong bonds) – very high melting point (strong bonds) – does not conduct (no delocalised electrons). Graphite – three covalent bonds for each carbon atom – layers of hexagonal rings – high melting point – layers free to slide as weak intermolecular forces between layers; soft, can be used as a lubricant – conduct thermal and electricity due to one delocalised electron per each carbon atom. Fullerenes – hollow shaped molecules – based on hexagonal rings but may have 5/7-carbon rings – C60 has spherical shape, simple molecular structure (Buckminsterfullerene). Nanotubes – cylindrical fullerene with high length to diameter ratio - High tensile strength (strong bonds) - Conductivity (deloc. electrons). Graphene - a single layer of graphite.
42
What is metallic bonding?
Forces of attraction between delocalised electrons and nuclei of metal ions.
43
Describe properties of metals.
High melting/boiling points (strong forces of attraction). Good conductors of heat and electricity (delocalised electrons). Malleable, soft (layers of atoms can slide over each other whilst maintaining the attraction forces).
44
What are alloys? Why are they harder than pure metals?
Alloys: mixtures of metal with other elements, usually metals. Different sizes of atoms distorts the layers, so they can’t slide over each other, therefore alloys are harder than pure metals.
45
What are the limitations of the simple model?
There are no forces between spheres and atoms, molecules and ions are solid spheres – this is not true.
46
What does the amount of energy needed to change state from solid to liquid or liquid to gas depend on?
The strength of the forces between the particles of the substance. The nature of the particles involved depends on the type of bonding and the structure of the substance. The stronger the forces between the particles the higher the melting point and boiling point of the substance.
47
A pure substance will melt or boil at…? What about the mixture?
A pure substance will melt or boil at a fixed temperature. A mixture will melt over a range of temperatures.
48
What are the three states of matter?
Solid, liquid and gas.
49
What is nanoscience?
Science that studies particles that are 1 - 100nm in size.
50
State the uses of nanoparticles.
Medicine (drug delivery systems), Electronics, Deodorants, Sun creams (better skin coverage and more effective protection against cell damage).
51
What are fine and coarse particles?
Fine particles (soot), 100-2500 nm diameter. Coarse particles (dust), 2500-105 nm diameter.
52
Why do nanoparticles have different properties to those for the same materials in bulk?
High surface area to volume ratio.

Chem Combined Higher (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions