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CHEMISTRY Flashcards

1
Q

What are atoms

A

The basic unit of matter,atoms consist of empty space with a positive nucleus at the centre

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2
Q

Where are protons found

A

Protons are found in the nucleus of an atom they have a larger mass than electrons. POSITIVE charge

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3
Q

Where are neutrons found

A

Found in the nucleus of an atom and have the same mass as protons. NEUTRAL charge

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4
Q

Where are electrons found

A

Electrons are spread out around the edge of an atom and are attracted to the protons in the nucleus. They orbit the nucleus in layers called shells. Negative charge

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5
Q

Electrical Charge

A

The atoms of an element contain equal numbers of protons and electrons so they overall have no charge

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6
Q

What are elements

A

Pure substances made of of only one type of atom, they cannot be broken down into simpler substances, all the atoms are identical. Eg are copper,helium,hyrdrogen,diamond,gold

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7
Q

What is the heaviest natural element

A

Uranium with 92 protons in each atom

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8
Q

What is a compound

A

made of two or more different types of atoms that are chemically bonded together. Eg) carbon dioxide and water

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9
Q

What is a pure substance

A

Pure substances are materials made of only one type of particle, either one kind of atom or a combination of atoms in a compound.

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10
Q

What is a mixture

A

Two or more substances that are NOT chemically bonded together, able to be seperated via chemical or physical means. eg) salt,brass

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11
Q

Metals Vs Non-metals

A

In the solid state,atoms of metals are held in a lattice, non-metals are usually gases at room temperature

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12
Q

What is a lattice

A

special pattern that shows how atoms or molecules are arranged in a solid

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13
Q

What are the two different types of gases

A

Monatomic= Gases made up of one atom eg)Neon
Diatomic= gases made up of 2 of the same atom. Eg) hydrogen,oxygen,nitrogen

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14
Q

Properties of metals

A
  • Lustrous
  • Hard
  • High density
  • High melting points(mercury is the only metal that is a liquid at room temperature)
  • Ductile
  • Malleable
  • Good conductors of heat and electricity
    Metal examples= Gold,copper,silver,zinc
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15
Q

Properties of Non-Metals

A
  • Dull but may be colourful
  • Poor thermal and electrical conductors
  • Brittle solids
  • Does not conduct electricity in a solid state
    Eg= Iodine,Fluorine,Phosphorus
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16
Q

Metalloids

A

Elements with properties of both metals and non-metals,found along the diagonal boundary between metals and non-metals in the periodic table. Eg) Boron,Silicon,Geranium

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17
Q

Periodic table

A

Metals are on the left and non-metals are on the right. Horizontal rows= Periods,Vertical rows= Groups

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18
Q

Chemical symbols

A

First letter is uppercase second letter is lower case

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19
Q

Mass number

A

The number of protons and neutrons in a atom(round the number)

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20
Q

Atomic number

A

The number of protons in the atom(smaller number)

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21
Q

Calculating number of protons,neutrons and electrons

A

Number of protons= Same as atomic number
Number of electrons= same as protons
Number of neutrons= mass number-atomic number

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22
Q

Noble gas

A

Elements in the last column of the periodic table,extremely inert gases.

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23
Q

Molecules

A

A group of two or more atoms held together by chemical bonds

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24
Q

Molecular elements

A

pure substances composed of one or more atoms of the same element Eg) oxygen,hydrogen,nitrgoen

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25
Molecular compound
molecular compounds are two or more non-metals bonded together by sharing electrons to form a molecule Eg0 water,carbon dioxide
26
Polymer
compounds made of molecules that are long chains of atoms
27
Natural Polymers
Come from plants,animals or micro-organisms. They break easily in nature Eg) rubber and cotton
28
Synthetic Polymers
Made by humans in factories, they dont break down easily. Eg)clothing fiers,plastic. All plastic are polymers
29
Why does a half eaten-apple go brown
The flesh of apple becomes oxidised by oxygen in the air. The reaction is catalysed by enzymes.
30
How is an explosion different from other chemical reactions
The chemical reaction in an explosion generates gases and heat at such a high rate that the mixture explodes/
31
Why does a spoonful of sugar dissolve more quickly than a sugar cube
The granulated sugar has a greater surface area in contact with the water than the cube
32
What makes a nail rust
A chemical reaction between iron and water and oxygen in the air
33
Why is the sydney harbour bridge continually being painted
To ensure that the steel will not rust in the moist,salty environment
34
Chemical reactions
The process in which reactants are transformed into products,involving the breaking and forming of chemical bonds between atoms. Eg)Digestion,washing,baking
35
Physical change
Change in shape or size or state that does not produce a new substance. Most are reversible and may look different but chemically its the same.
36
When can physical change occur
- When force is applied - Substance is broken down - Substance changes state(solid,liquid,gas)
37
How is a burning candle a physical and chemical change
Physical= Melting of a solid wax to a liquid wax. Evaporation of liquid wax to wax vapour. Chemical= Burning of the wax vapour, reacts with oxygen in the air to form a new substance like carbon and ash
38
Changes of state
solid to liquid= MELTING Liquid to solid = FREEZING Liquid to gas = EVAPORATION Gas to liquid =CONDENSATION Solid to gas = SUBLIMATION Gas to solid = DEPOSITION
39
Melting and Boiling points
Less than melting points = Solid In between melting and boiling points = Liquid More than boiling point = Gas
40
Identifying chemical change
- Colour change - Odour - Gas is produced(seeing bubbles) - A solid(Precipitate) forming in a solution - Energy is produced or observed in heat,light,sound
41
What is a precipitate
When two solutions are mixed a new solid is produced, which indicates a chemical change
42
Two types of energy
Exothermic = Releases energy ( feels hot) Endothermic = Absorbs energy (feels cold)
43
Word equations
when chemical changes occur the atoms in the molecules re-arrange to form a different combination of atoms. Chemical reactions break bonds and form new bonds,therefore producing a new substance.
44
Reactants
Substances you start with
45
Products
Substances you end with
46
Burning in air
Oxygen
47
Reaction rate
Speed at which a reaction takes place
48
What factors can affect the rate of a reaction
- Temperature - Pressure/volume - Size - Concentration - Adding a catalyst
49
Particles in a solid
Very close together
50
Particles in a liquid
More separated
51
Particles in a Gas
Very far away from eachother
52
Is it true that particles are always moving
Yes particles always move
53
Collision theory
For substances to react, their particles must come into contact with each other (collide) The more collisions that happen between particles, the more likely they will react.
54
Size
The smaller the size of the particle, the faster the rate of reaction Smaller particles have greater total surface area, therefore a higher chance of collision
55
Temperature
When heat energy is added to the substance, the particles gain kinetic energy and therefore move quicker If the particles are moving around more quickly, it is most likely they are also going to collide more often If the temperature is reduced, than so to is the kinetic energy and chance of collisions
56
Concentration
Concentration refers to how many particles of one type there are, in a particular area More concentrated substances will react more easily, as there is a higher chance of collision. This is because there are more particles to collide.
57
Catalyst
Catalysts are chemicals that speed up reactions, but are left unchanged after the reaction has been completed. Some catalysts (such as enzymes) increase the rate of reaction by temporarily binding with the reactants and providing them with the correct orientation for a successful collision to occur.
58
Enzymes- Biological catalysts process
1- Single atoms 2- Atoms bonding on enzymes 3- Bonded molecules
59
How do enzymes help in a chemical reaction
Only speed up one reaction at a time They help chemicals to collide more easily They lower the activation energy needed to start the reaction making the reaction occur faster.
60
What is distilled water,is it the same as pure water
Distilled water is water that has been boiled to remove impurities and then cooled back into liquid form. It is a type of pure water, but pure water can also be made in other ways, like through filtering or chemical processes.
61
Name three metals that have similar properties to magensium
Aluminum(Al),Calcium(Ca) and Zinc(Zn)
62
Give an example of a physical change and explain why it is a physical change
Melting of ice into water as it can be easily reversed. Change in shape or size or state that does not produce a new substance. Most are reversible and may look different but chemically its the same.
63
What happens to molecules in water when they change state from a liquid to a gas
When water changes from a liquid to a gas, the molecules gain enough energy to move farther apart and spread out, turning into steam or water vapor
64
What happens to molecules in water when they change state from a gas to liquid
When water changes from a gas to a liquid, the molecules lose energy, slow down, and move closer together, forming liquid water.
65
How is boiling water a physical change
No new substances are formed only changes from liquid to gas.
66
What is the difference between melting and sublimation
Melting is the process where a solid turns into a liquid, while sublimation is when a solid changes directly into a gas without passing through the liquid state.
67
What is the difference between solidification and freezing
Solidification is when a liquid turns into a solid, and freezing is the specific process of a liquid turning into a solid as it gets colder.
68
How is heating chocolate a physical and chemical change
It is a physical change when it melts as it only just changes shape, it is chemical change when it burns as it turns into a new substance like ash
69
One method of increasing the combustion of the wood is to add more reactants how is the paper fanning doing this?
Fanning a fire adds oxygen and increases the rate of burning
70
Increasing the surface area of wood also helps. How has the camper achieved this
The camper has chopped the wood into smaller pieces, allowing a greater surface area of wood to come into contact with oxygen
71
What are plastics made from
Plastics are made from chains of molecules called polymers
72
Recycling Plastics
Plastics are non-biodegradable. Plastics are made from oil. Oil is expensive and non-renewable.
73
Subatomic particle
Particle that is smaller than a atom, such as protons,neutrons and electrons which make up the structure of an atom.
74
How are elements arranged in the periodic table
Arranged based on the size of the atom and properties of elements.
75
Chemical change
A process in which the chemical composition if a substance is altered,resulting in new products.

Science (10 decks)

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