iGCSE Chemistry: 1 i) Electrolysis, iGCSE Chemistry: 1 a) States of matter, iGCSE Chemistry: 1 b) Atoms, iGCSE Chemistry: 1 c) Atomic structure, iGCSE Chemistry: 1 d) Relative formula masses and molar volumes of gases, iGCSE Chemistry: 1 e) Chemical...

An atom of sodium loses one electron. An atom of chlorine gains one electron

Describe, in terms of electrons, the formation of sodium chloride

chlorine

Name the product formed at the anode during the electrolysis of molten copper chloride

paper chromatography

State the method used to obtain red food dye from a mixture of food dyes

filtration

State the method used to obtain sand from a mixture of sand and water

crystallisation

State the method used to obtain solid copper sulfate from aqueous copper sulfate

simple distillation

State the method used to obtain water from salt water

White solid formed

State the observation in the reaction between HCl(g) and NH₃(g)

Electrons

State the particle that is found in the shells orbiting the nucleus

Protons and neutrons

State the particles that are found within the nucleus of an atom

1) mass/Ar. 2) divide by the smallest. 3) Give the ratio has a whole number. 4) State final empirial formula

State the steps for calculating empirical formula

platinium

Suggest a suitable element for the electrode for the electrolysis of water

increases electrical conductivity

Suggest why a small amount of dilute acid is added to water before it is electrolysed

tungsten oxide

Tungsten has the chemical symbol W. Suggest the chemical name of WO₃.

mass / amount (in moles)

Using relative atomic mass (Ar) and relative formula mass (Mr), complete the following expression: Mr =

mass / Mr

Using relative atomic mass (Ar) and relative formula mass (Mr), complete the following expression: amount (in moles) =

amount (in moles) / Mr

Using relative atomic mass (Ar) and relative formula mass (Mr), complete the following expression: mass =

257

Calculate the relative formula mass(Mr) of zinc phosphide (Zn₃P₂)

2Br⁻ → Br₂ + 2e⁻

Write the ionic half-equation for the reaction that takes place at the anode during the electrolysis of lead(II) bromide

Pb²⁺ +2e⁻ → Pb

Write the ionic half-equation for the reaction that takes place at the cathode during the electrolysis of lead(II) bromide

P³⁻

Zinc phosphide, Zn₃P₂ is an ionic compound. The formula of the zinc ion is Zn²⁺. Deduce the formula of the phosphide ion

A molecule is made of a fixed number of two or more atoms covalently bonded together

What is meant by the term molecule?

The average mass of an atom of an element, relative to 1/12th of the mass of an atom of carbon-12

What is meant by the term relative atomic mass, Ar?

positive

What is the charge of the anode?

negative

What is the charge of the cathode?

MgCl₂

What is the formula of magnesium chloride

fractional distillation

State the method used to obtain kerosene from a crude oil.

3

How many different elements are there in Be(OH)₂ ?

2+

A magnesium ion has the electron configuration 2.8.2. What is the charge on the ion?

((79x50.7)+(81x49.3))/100 = 79.99

A sample of bromine contained the two isotopes in the following proportions: bromine-79 = 50.7% and bromine-81 = 49.3%. Calculate the relative atomic mass of bromine

((12x98.90)+(13x1.10))/100 = 12.01

A sample of carbon contained 98.90% carbon-12 and 1.10% carbon-13. Calculate the relative atomic mass of carbon

4 HCl(aq) + MnO₂(s) -> MnCl₂(aq) + 2H₂O(l) + Cl₂(g)

Balance the equation for the reaction: ___ HCl(aq) + ___ MnO₂(s) -> ___MnCl₂(aq) + ___H₂O(l) + ___ Cl₂(g)

WO₃ + 3H₂ -> W + 3H₂O

Balance the following equation: WO₃ + H₂ -> W + H₂O

Suggest why buckminsterfullerene, C60, has a low melting point.

Buckminsterfullerene has a simple molecular structure with weak intermolecular forces that require little energy to overcome

The electrostatic attraction between a regular array of positive ions and the sea of delocalised electrons

Define metallic bonding

1) Grind rock salt into a fine powder. 2) Add powder to hot water and stir to dissolve salt. 3) Filter mixture. Salt solution passes through the filter paper leaving behind the sand. 4) Boil filtrate to evaporate some of the water. 5) Leave saturated solution to cool so that crystals of salt form. 6) Filter cold mixture to separate the crystals from the remaining solution.

Describe how pure salt can be obtained from rock salt

Particles are close together but irregular. The particles are free to move.

Describe the arrangement and movement of the particles in a liquid

Particles are far apart and there are no forces between them. Energy is high. The particles move quickly and freely.

Describe the arrangement, movement and energy of the particles in a gas

Particles are close together and regularly packed. Energy is low. The particles vibrate around a fixed point.

Describe the arrangement, movement and energy of the particles in a solid

Arrangement becomes more regular. Particles vibrates in a fixed position. Particles lose energy

Describe the changes in arrangement, movement and energy of particles when a liquid cools to become a solid

The particles form a regular arrangement, they slow down and lose kinetic energy

Describe the changes in arrangement, movement and energy of particles when a liquid turns into a solid

The sharing of a pair of electrons between two nuclei

Describe the formation of a covalent bond

A giant structure held together by the attraction between oppositely charged ions

Describe the structure of an ionic compound, e.g NaCl. (Triple science only!)

Metals have a giant regular structure of positive ions surrounded by a sea of delocalised electrons

Describe the structure of metals

X=boiling, Y=condensing, Z=freezing

Draw 3 particle diagrams to show the arrangement of particles in a solid, liquid and gas. Draw arrows between them and label boiling, condensing and freezing

These diagrams represent the particles in an element (2), a compound and a mixture, but which is which?

Draw 4 diagrams to show the particles in i) element, ii) compound, iii) mixture, iv) element

A - sodium ions. B - Chloride ions

Draw a diagram to represent the positions of the ions in a crystal of sodium chloride.

A - sodium ions. B - Chloride ions

Draw a diagram to represent the positions of the ions in a crystal of sodium chloride. (Triple science only!)

For what process is this equipment used?

Draw a diagram to show equipment used in simple distillation

What does this represent?

Draw the arrangement of particles in a solid, liquid and gas

For what process is this equipment used?

Draw the equipment used in fractional distillation in the lab

A small molecule such as H₂0 or HCl

During condensation polymerisation, what else forms other than the polymer? (Triple science only!)

Amount of Cl₂ = 18/24000 = 0.00075mol. Charge = 0.00075 x 965000 x 2 = 144.45C

During the electrolysis of sodium chloride solution, chlorine gas is produced. The equation for its formation is: 2Cl⁻ → Cl₂ + 2e⁻ Calculate the quantity of electricity, in coulombs, needed to produce 18cm³ of chlorine gas. (Triple science only!)

4OH⁻ ->2H₂O + O₂ + 4e⁻

During the electrolysis of water, oxygen gas is given off. The formation of this gas can be represented by the ionic equation: ....OH⁻ →....H₂O + ....O₂ + ....e− (Triple science only!)

Silica has a giant covalent structure with many strong covalent bonds that need a lot of energy to break

Explain why Silica, SiO₂ is a solid with a high melting point

The numbers of electrons and protons are equal

Explain why atoms are neutral

electrons in the outer shell

Elements in the same group in the Periodic Table have the same number of....

Use a water bath

Ethanol is a flammable liquid. Suggest how it could be heated safely

Each dyes has a different mixture

Explain how a chromatogram shows that different dyes are different from each other

The different liquids have different boiling points

Explain how fractional distillation is used to separate a mixture of different liquids

Strong attraction between a shared pair of electrons and two nuclei

Explain the term covalent bond

An ionic bond is the strong electrostatic attraction between oppositely charged ions

Explain the term ionic bond

Oxidation is the loss of electrons (the term is also used for the gain of oxygen)

Explain the term oxidation

Reduction is the gain of electrons (the term is also used for the loss of oxygen)

Explain the term reduction

The rate of flow of charge particles (e.g. of electrons or ions)

Explain what is meant by electric current

The breakdown of a substance using electricity

Explain what is meant by electrolysis

Mg²⁺ and O²⁻ ions have a higher charge than sodium and chloride therefore the electrostatic forces between the ions are much stronger. This requires more energy to break.

Explain why magnesium oxide has a higher melting point than sodium chloride. (Triple science only!)

Metals have layers of atoms that can slide over each other

Explain why metals are ductile/malleable

Metals have delocalised electrons which are free to move

Explain why metals are good conductors of electricity

Nitrogen has a simple molecular structure with weak intermolecular forces that require little energy to overcome

Explain why nitrogen gas, N₂, is a gas at room temperature

Isotopes have the same number of electrons

Explain, in terms of electrons, why isotopes have the same chemical properties

Graphite has weak intermolecular forces of attraction between layers. These layers can slide over each other

Explain, in terms of its structure, why graphite can act as a lubricant. (Triple science only!)

Graphite has delocalised electrons which can move

Explain, in terms of its structure, why graphite can conduct electricity. (Triple science only!)

NaCl and MgO both have a giant ionic structure with strong electrostatic forces between oppositely charged ions. The Ions in MgO have a charge of 2 and -2, but in NaCl the charges are 1 and -1. So the bonds in MgO require more energy to break

Explain, in terms of structure and bonding, why magnesium oxide has a higher melting point than sodium chloride (Triple science only!)

NaCl has a giant ionic structure with strong electrostatic forces between oppositely charged ions that require a lot of energy to break

Explain, in terms of structure and bonding, why sodium chloride has a very high melting point

Gas particles collide with air particles and move in random directions

Gas particles move at a speed of several hundred metres per second at room temperature. Explain why gases take several minutes to diffuse across a room

Strong attraction between a shared pair of electrons and two nuclei

Give the definiton of a covalent bond

Put it in a circuit including a bulb. If the bulb light then the liquid is an electrolyte

How could you determine if a liquid is an electrolyte?

Gas or liquid (low melting point)

If a substance has a simple molecular structure, what physical state might it be at room temperature?

Molar volume = amount (in moles) x 24 dm³ or 24,000 cm³

State the expression for calculating molar volume of a gas. (Triple science only!)

hydrogen

Name the product formed at the cathode during the electrolysis of water. (Triple science only!)

1

State the mass of a neutron

1

State the mass of a proton

almost 0

State the mass of an electron

dissolving

State the method used to extract the red dye from a sample of rose petals

Gas diffuses quicker because particles have more energy.

State and explain how increasing temperature affects the diffusion of a gas

0

State the charge of a neutron

+1

State the charge of a proton

-1

State the charge of an electron

2.8.8

State the electron configuration of a chloride ion

2.8

State the electron configuration of a sodium ion

% yield = (actual amount of products/theoretical amount of products) x100

State the expression for calculating % yield. (Triple science only!)

Molar concentration = Amount (in moles)/volume (in dm^³)

State the expression for calculating molar concentration

atomic number

The elements in the Periodic Table are arranged in order of increasing.....

10/2 = 5 mol

The equation for the reaction taking place at the positive electrode during the electrolysis of sodium choride solution is 2Cl⁻(aq) → Cl₂(g) + 2e⁻ Ten faradays (10 F) of electricity were passed through an aqueous solution of sodium chloride. Calculate the amount, in moles, of chlorine formed. (Triple science only!)

482500/(2 x 96500) = 2.5 mol

The equation which represents the formation of hydrogen gas at the negative electrode during the electolysis of water is 2H₂O(l) + 2e⁻ → 2OH⁻(aq) + H₂(g) During electrolysis, 482 500 coulombs were passed through the solution. Calculate the amount, in moles, of hydrogen gas formed. (Triple science only!)

The number of moles of H₂ are twice that of oxygen

The overall equation for the decomposition of water is: 2H₂O(l) -> 2H₂(g) + O₂(g) Use this equation to explain why the volume of hydrogen collected should be twice that of the volume of oxygen. (Triple science only!)

Moles

What are the units for amount in Chemistry?

(s) - solid. (l) - liquid. (g) - gas. (aq) - aqueous (in solution)

What do each of the following state symbols represent: (s), (l), (g), (aq)

A Faraday is the charge on a mole of electrons (96500 Coulombs)

What is a Faraday? (Triple science only!)

6 x 10^²³. It is equivalent to the number of atoms in 12 g of 12 C.

What is avagadro's number, and to what is it equivalent? (Triple science only!)

An atom is the smallest part of an element

What is meant by the term atom?

The number of protons in an atom

What is meant by the term atomic number?

A compound is a substance that contains two or more elements chemically joined together

What is meant by the term compound?

An element is a substance made of only one type of atom

What is meant by the term element?

Atoms of the same element (same number of protons) but with a different number of neutrons

What is meant by the term isotope?

The number of protons plus the number of neutrons in an atom

What is meant by the term mass number?

Different substances in the same space, but not chemically combined.

What is meant by the term mixture?

The volume of 1 mole of gas at r.t.p is called the molar volume (24dm³ or 24000cm³)

What is the meaning of the term Molar Volume? (Triple science only!)

A mole is the amount of a substance found in its relative formula mass in grams (e.g. in 24g of Magnesium)

What is the meaning of the word mole in Chemistry?

5

What is the total number of atoms in the formula Be(OH)₂ ?

Diffusion

What name is given to the movement of gases?

Condensation polymerisation

What type of reaction is used to form nylon? (Triple science only!)

oxidation

What type of reaction takes place at the anode?

reduction

What type of reaction takes place at the cathode?

Electron

Which particle in an atom has a negative charge?

Electron

Which particle in an atom has the smallest mass?

There are no charged particles that are free to move

Why do covalent compounds (e.g H₂O) not conduct electricity?

When solid the ions are held in place. When molten or in solution the ions are free to move

Why do ionic compounds conduct electricity only when molten or in solution?

HCl + NH₃ -> NH₄Cl

Write a chemical equation for the reaction between hydrogen chloride and ammonia

2Cl⁻ → Cl₂ + 2e⁻

Write an equation to show the formation of the product at the anode during the electrolysis of copper chloride

Cu²⁺ +2e⁻ → Cu

Write an equation to show the formation of the product at the cathode during the electrolysis of copper chloride

2.8

Write the electronic configuration of argon

2.8.8.1

Write the electronic configuration of potassium