GCSE OCR Chemistry A Papers 1 and 3 Automarked

#1. What is the difference in concentration between pH 6 and pH 4?

1x

100x

10,000x

10x

1000x

#2. How many atoms of potassium (group 1) are needed to bond ionically with oxygen (group 6)?

2

3

1

#3. What is the chemical symbol for copper?

#4. What is the formula for hydrochloric acid?

NaOH

HNO₃

Ca(OH)₂

H₂SO₄

HCL

KOH

#5. Because mixtures contain more than one substance and each has its own melting point, mixtures melt in which way?

over a range of temperatures

at a specific point

#6. During Ernest Rutherford’s experiments with gold foil, why did some of the particles bounce back?

Alpha particles are positively charged, they were deflected when they met the positively charged protons in the nucleus

He fired electrons at the gold foil and when they met protons they were reflected back

Alpha particles behave in unpredictable ways and can randomly change direction due to quantum effects

#7. Isotopes of atoms have different numbers of which particles?

Protons

Neutrons

#8. True or false – You cannot use physical processes to separate mixtures into different substances.

True

False

#9. Which of the following items would you need to perform crystallisation by heating? ? 6 items

Select all that apply:

a heatproof mat

filter paper

a beaker

an evaporating basin

tripod

gauze

a bunsen burner

filter funnel

#10. Which types of atoms can be found in a pure piece of gold?

Select all that apply:

carbon atoms

gold atoms

trace amounts of other elements

#11. What is the name of the phase change from gas to liquid?

condensation

freezing

evaporation/boiling

sublimation

deposition

melting

#12. What is the chemical symbol for potassium?

#13. When using inert electrodes to perform electrolysis with water acidified with sulfuric acid, which products will be produced at the anode and cathode?

Cathode: Hydrogen (H₂) Anode: Hydroxide (OH⁻)

Cathode: Hydroxide (OH⁻) Anode: Hydrogen (H₂)

Cathode: Hydrogen (H₂) Anode: Sulfate (SO₄²⁻)

#14. What is the chemical symbol for magnesium?

#15. Fill in the gap. Metal atoms bond forming a giant ……… of ions.

Anchor

Lattice

Ball

Lettuce

#16. Which type of reaction is aerobic respiration?

Endothermic

Exothermic

Ectothermic

Mesothermic

#17. What are positive ions called?

cations

anions

#18. What is the formula for the polyatomic ion nitrate?

SO₄²⁻

OH⁻

NO₃⁻

CO₃²⁻

SO₃²⁻

NH₄⁺

#19. Calculate the relative formula mass of water. Hydrogen Aᵣ = 1, Oxygen Aᵣ = 16.

#20. After paper chromatography has been carried out, the paper is known as?

a still

a chromatogram

a wet piece of paper

#21. What is the mass number of an element?

the number of protons plus neutrons

the total number of subatomic particles in an atom

#22. Which of these are common properties of giant covalent materials?

High melting/boiling points

Soluble in water

Conduct electricity

Do not conduct electricity

Insoluble in water

Low melting/boiling points

#23. How could you separate a mixture of sand and salt?

fill a container with water to dissolve the salt, then filter out the sand and evaporate the water

add water and then use fractional distillation to separate the sand and water and you will be left with the salt

use paper chromatography to separate the sand from the salt

#24. What is a solution called when it contains the maximum amount of solute that can dissolve in a solvent at a particular temperature?

flaccid

dilute

saturated

#25. What is the chemical symbol for radon?

#26. Displacement reactions sometimes occur between a metal and a compound of a less reactive metal. Are these reactions endothermic or exothermic?

Endothermic

Exothermic

#27. Why is magnesium a better electrical conductor than sodium?

Group 2 magnesium has two spare electrons to donate to the delocalised pool, whereas, sodium atoms only have one electron to donate. This means there are more electrons to carry the charge

Group 1 sodium is less electrically conductive because it quickly forms impurities that prevent efficient conduction

#28. Ernest Rutherford fired positive particles at a thin gold foil and showed that most of atoms is empty space. Which particles did he fire at the gold foil?

beta particles

gamma rays

alpha particles

#29. Which of the following are 3 of the adaptations of leaves for efficient photosynthesis?

Select all that apply:

Large leaves - bigger surface area

Leaves have stomata - for gaseous exchange

Root hair cells are thin and very numerous - increasing surface area

Flat leaves - reduces distance for diffusion of gases

Leaves retract inside stems overnight - avoiding water loss

Remember to carefully read the question, if you selected Root hair cells, you were mistaken because the question asked about leaves, not roots.

#30. What is graphene?

Graphene is the material that forms from the covalent bonding of oxygen and nitrogen

Graphene is a layer of graphite that is one atom thick

Graphene is a small section of a diamond

#31. H₂SO₄(aq) + Na₂O(s) → …. + ….

Select all that apply:

Na₂SO₄(aq)

2H₂O (l)

NaOH

MgOH

H₂O (l)

#32. During a neutralisation reaction which salt is formed from hydrochloric acid?

nitrate

borate

sulfate

carbonate

chloride

#33. Which of these is a problem with dot and cross diagrams?

The model does not show that the ions will be constantly vibrating

The model shows the atoms as being too far apart and there are no sticks

They do not show how the structure formed and suggest that the electrons in different atoms are different, but they are actually the same

#34. Do non-metals usually have a high or low density?

Low

High

#35. Which of the following was the Rutherford Model of atomic structure?

A mass of positively charged material with negatively charged electrons distributed throughout it

A central nucleus containing protons and neutrons, surrounded by electrons

#36. Paper chromatography is used to separate which types of materials?

separating soluble compounds

separate different types of liquids

separate soluble materials from insoluble materials

#37. Do non-metals usually have a high or low melting point?

High

Low

#38. What state of matter has particles which are close together and vibrate around fixed positions?

gases

liquids

solids

#39. Oxygen is in group 6 and fluorine is in group 7. How many fluorine atoms bond with one oxygen atom?

#40. What is the formula for the polyatomic ion ammonium?

NO₃⁻

NH₄⁺

CO₃²⁻

SO₃²⁻

SO₄²⁻

OH⁻

#41. Is water an example of a covalent compound?

No

Yes

#42. What is the chemical symbol for nitrogen?

#43. What is the charge of an electron?

0

+1

-1

#44. What are ions?

atoms which have different numbers of protons

atoms which have gained or lost electrons

atoms which have different numbers of neutrons

#45. What do group 2 atoms do when they bond with group 6 atoms?

lose two neutrons

gain two electrons

gain one proton

lose two electrons

#46. What is the chemical symbol for calcium?

#47. Are non-metals usually malleable or brittle?

Malleable

Brittle

#48. What is the name of the process by which salt is removed from water?

unsaturation

demicronation

desalination

#49. Most ionic bonds are formed between which groups?

metals and non-metals

metals and metals

non-metals and non-metals

#50. During a neutralisation reaction which salt is formed from sulfuric acid?

Nitrate

Carbonate

Sulfate

Chloride

Borate

#51. What is the freezing point of water?

30˚C

66.5˚C

55˚C

0˚C

25˚C

100˚C

#52. Determine the empirical formula of glucose – C₆H₁₂O₆.

C₂H₂O

C₂OH

CH₂O

CHO₂

#53. Why is diamond hard?

Diamond is hard because carbon atom is covalently bonded to 4 other carbon atoms, in a tetrahedral arrangement.

Diamond is hard because it is made of ionically bonded carbon atoms.

Diamond is hard because it is composed of particular isotopes of carbon with extra neutrons, making the material more dense

#54. Chlorine has two stable isotopes, ³⁵Cl (75.77%) and ³⁷Cl (24.23%). Calculate the Aᵣ of chlorine to 2 decimal places.

#55. Fractional distillation is used to separate which types of materials?

separate different types of liquids

separate soluble materials from insoluble materials

separating soluble compounds

#56. True or false – Precipitation reactions can be either exothermic or endothermic.

True

False

#57. What are giant covalent structures?

Ionically bonded substances such as sodium bromide

a structure where each atom has a covalent bond to its neighbour

a compound which contains atoms covalently bonded together, but with weak intermolecular forces between molecules

#58. The melting point of gallium is 29.8˚C and the boiling point is 2204˚C. What state is gallium at 25˚C?

gas

solid

liquid

#59. Calculate the relative formula mass of copper oxide (CuO) to 2 decimal places. Copper Aᵣ = 63.5, Oxygen Aᵣ = 16.

#60. If covalent bonds are very strong, then why does water have a low melting point?

The bonds between hydrogen and oxygen are weaker than typical covalent bonds

Water has a high melting point

There are only weak intermolecular forces between the molecules in water. The atoms remain bonded whilst the molecules become separated.

#61. Which scientist proposed the Plum Pudding Model?

John Dalton

JJ. Thomson

Ernest Rutherford

#62. Solutions of less than pH 7 are?

neutral

acidic

alkaline

#63. When using inert electrodes to perform electrolysis with molten lead bromide, which products will be produced at the anode and cathode?

Cathode: Bromine (Br₂) (g) Anode: Lead (Pb) (s)

Cathode: Lead (Pb) (s) Anode: Bromine (Br₂) (g)

Cathode: Hydrogen (H₂) (g) Anode: Lead (Pb) (s)

#64. The table shows 3 substances and their melting points. What common substance, in particular, could substance Z be?

#65. Lead has 4 stable isotopes. ²⁰⁴Pb (abundance – 1.4%), ²⁰⁵Pb (abundance – 24.1%), ²⁰⁷Pb (abundance – 22.1%) and ²⁰⁸Pb (abundance – 52.4%). Calculate the Aᵣ of lead. Answer to 2 decimal places.

#66. Which of the following descriptions matches the Aᵣ of an element?

The mean mass of an atom compared with carbon-12

The simplest whole number ratio of atoms

The sum of the relative atomic masses of all of the atoms or ions in its formula

#67. Complete the following equation: MgO (s) + H₂SO₄ (aq) → …. + ….

Select all that apply:

MgSO₄ (aq)

MgS₂

HO (l)

MgS (g)

H₂O (l)

Neutralisation reactions follow the general structure –

metal oxide acid = salt water

the acid produces hydrogen ions and the metal oxide produces oxide ions – these combine to make the water

the salt is comprised of the remaining products – the metal and the other element from the acid

in this case, the other element is chlorine

The naming convention is to put the metal first for the salt created

#68. Determine the empirical formula for Cyanuric triazide – C₃N₁₂.

C₄N₄

C₂N₄

CN

CN₄

#69. What is the name of the phase change from liquid to gas?

deposition

melting

freezing

condensation

evaporation/boiling

sublimation

#70. What do group one atoms do when they bond ionically with group 7 atoms?

gain two electrons

lose one electron

gain one electron

lose two electrons

#71. Which type of reaction transfers energy to the surroundings?

Endothermic

Exothermic

Mesothermic

#72. Are non-metals usually good conductors of heat?

No

Yes

#73. Filtration and crystallisation are used to separate which types of materials?

separating soluble compounds

separate different types of liquids

separate soluble materials from insoluble materials

#74. After filtering a mixture containing sand, salt and water using filter paper. What do we call what is left in the filter paper?

Leftovers

Remainder

Residue

#75. Which of these is the correct explanation for why photosynthesis is slower at lower temperatures?

At low temperatures particles are unable to react because they each need to be thermally activated which happens at 23˚C.

At low temperatures particles exert a very slight repulsive force against each other, preventing the necessary reactions for photosynthesis.

At low temperatures particles are moving slowly and collide less often. These collisions are necessary for reactions to take place, such as photosynthesis.

#76. What is the chemical symbol for carbon?

#77. Since metallically bonded atoms have a delocalised pool of electrons, these electrons are able to conduct ……

Select all that apply:

Electricity

Electromagnetic waves

Sound

Heat

#78. A paper chromatography experiment is carried out in a lab. The distance moved by the spot was 6cm and the solvent had moved by 8cm. Calculate the Rf value.

#79. What state of matter has particles which are far apart and move around independently?

gases

liquids

solids

#80. Solutions of more than pH 7 are?

alkaline

acidic

neutral

#81. What is the formula for the polyatomic ion carbonate?

SO₄²⁻

SO₃²⁻

NO₃⁻

OH⁻

CO₃²⁻

NH₄⁺

#82. Covalent compounds typically form between which two types of material?

non-metal and non-metal

metal and non-metal

metal and metal

#83. When using inert electrodes to perform electrolysis with sodium sulfate solution, which products will be produced at the anode and cathode?

Cathode: Sodium (Na) Anode: Hydroxide (OH⁻)

Cathode: Hydrogen (H₂) Anode: Sulfate (SO₄²⁻)

Cathode: Hydrogen (H₂) Anode: Hydroxide (OH⁻)

#84. Which of the following are properties of ionic compounds?

low melting and boiling points

usually soluble

conduct electricity when molten or dissolved

high melting and boiling points

conduct electricity as solids

usually insoluble

#85. Neutralisation reactions which occur between an acid and a base are always:

Exothermic

Endothermic

#86. Reaction profiles are used to show the energy transfers during reactions. Which type of reaction is shown in this reaction profile?

Ectothermic

Exothermic

Mesothermic

Endothermic

#87. What temperature is the boiling point of water?

#88. Complete the equation: HCl (aq) + KOH(s) → ….. + …..

Select all that apply:

O

ClOH

KCl

H₂O

H₂

#89. The distance travelled by a spot is determined by the solubility of the compound. How does solubility impact distance travelled?

More soluble - greater distance

More soluble - shorter distance

#90. Which electrode would the ion Mg²⁺ migrate to during electrolysis?

Neither

Cathode

Anode

GCSE OCR Chemistry Papers 1 and 3

Results

#1. What is the difference in concentration between pH 6 and pH 4?

#2. How many atoms of potassium (group 1) are needed to bond ionically with oxygen (group 6)?

#3. What is the chemical symbol for copper?

#4. What is the formula for hydrochloric acid?

#5. Because mixtures contain more than one substance and each has its own melting point, mixtures melt in which way?

#6. During Ernest Rutherford’s experiments with gold foil, why did some of the particles bounce back?

#7. Isotopes of atoms have different numbers of which particles?

#8. True or false – You cannot use physical processes to separate mixtures into different substances.

#9. Which of the following items would you need to perform crystallisation by heating? ? 6 items

#10. Which types of atoms can be found in a pure piece of gold?

#11. What is the name of the phase change from gas to liquid?

#12. What is the chemical symbol for potassium?

#13. When using inert electrodes to perform electrolysis with water acidified with sulfuric acid, which products will be produced at the anode and cathode?

#14. What is the chemical symbol for magnesium?

#15. Fill in the gap. Metal atoms bond forming a giant ……… of ions.

#16. Which type of reaction is aerobic respiration?

#17. What are positive ions called?

#18. What is the formula for the polyatomic ion nitrate?

#19. Calculate the relative formula mass of water. Hydrogen Aᵣ = 1, Oxygen Aᵣ = 16.

#20. After paper chromatography has been carried out, the paper is known as?

#21. What is the mass number of an element?

#22. Which of these are common properties of giant covalent materials?

#23. How could you separate a mixture of sand and salt?

#24. What is a solution called when it contains the maximum amount of solute that can dissolve in a solvent at a particular temperature?

#25. What is the chemical symbol for radon?

#26. Displacement reactions sometimes occur between a metal and a compound of a less reactive metal. Are these reactions endothermic or exothermic?

#27. Why is magnesium a better electrical conductor than sodium?

#28. Ernest Rutherford fired positive particles at a thin gold foil and showed that most of atoms is empty space. Which particles did he fire at the gold foil?

#29. Which of the following are 3 of the adaptations of leaves for efficient photosynthesis?

#30. What is graphene?

#31. H₂SO₄(aq) + Na₂O(s) → …. + ….

#32. During a neutralisation reaction which salt is formed from hydrochloric acid?

#33. Which of these is a problem with dot and cross diagrams?

#34. Do non-metals usually have a high or low density?

#35. Which of the following was the Rutherford Model of atomic structure?

#36. Paper chromatography is used to separate which types of materials?

#37. Do non-metals usually have a high or low melting point?

#38. What state of matter has particles which are close together and vibrate around fixed positions?

#39. Oxygen is in group 6 and fluorine is in group 7. How many fluorine atoms bond with one oxygen atom?

#40. What is the formula for the polyatomic ion ammonium?

#41. Is water an example of a covalent compound?

#42. What is the chemical symbol for nitrogen?

#43. What is the charge of an electron?

#44. What are ions?

#45. What do group 2 atoms do when they bond with group 6 atoms?

#46. What is the chemical symbol for calcium?

#47. Are non-metals usually malleable or brittle?

#48. What is the name of the process by which salt is removed from water?

#49. Most ionic bonds are formed between which groups?

#50. During a neutralisation reaction which salt is formed from sulfuric acid?

#51. What is the freezing point of water?

#52. Determine the empirical formula of glucose – C₆H₁₂O₆.

#53. Why is diamond hard?

#54. Chlorine has two stable isotopes, ³⁵Cl (75.77%) and ³⁷Cl (24.23%). Calculate the Aᵣ of chlorine to 2 decimal places.

#55. Fractional distillation is used to separate which types of materials?

#56. True or false – Precipitation reactions can be either exothermic or endothermic.

#57. What are giant covalent structures?

#58. The melting point of gallium is 29.8˚C and the boiling point is 2204˚C. What state is gallium at 25˚C?

#59. Calculate the relative formula mass of copper oxide (CuO) to 2 decimal places. Copper Aᵣ = 63.5, Oxygen Aᵣ = 16.

#60. If covalent bonds are very strong, then why does water have a low melting point?

#61. Which scientist proposed the Plum Pudding Model?

#62. Solutions of less than pH 7 are?

#63. When using inert electrodes to perform electrolysis with molten lead bromide, which products will be produced at the anode and cathode?

#64. The table shows 3 substances and their melting points. What common substance, in particular, could substance Z be?

#65. Lead has 4 stable isotopes. ²⁰⁴Pb (abundance – 1.4%), ²⁰⁵Pb (abundance – 24.1%), ²⁰⁷Pb (abundance – 22.1%) and ²⁰⁸Pb (abundance – 52.4%). Calculate the Aᵣ of lead. Answer to 2 decimal places.

#66. Which of the following descriptions matches the Aᵣ of an element?

#67. Complete the following equation: MgO (s) + H₂SO₄ (aq) → …. + ….

#68. Determine the empirical formula for Cyanuric triazide – C₃N₁₂.

#69. What is the name of the phase change from liquid to gas?

#70. What do group one atoms do when they bond ionically with group 7 atoms?

#71. Which type of reaction transfers energy to the surroundings?

#72. Are non-metals usually good conductors of heat?

#73. Filtration and crystallisation are used to separate which types of materials?

#74. After filtering a mixture containing sand, salt and water using filter paper. What do we call what is left in the filter paper?

#75. Which of these is the correct explanation for why photosynthesis is slower at lower temperatures?

#76. What is the chemical symbol for carbon?

#77. Since metallically bonded atoms have a delocalised pool of electrons, these electrons are able to conduct ……

#78. A paper chromatography experiment is carried out in a lab. The distance moved by the spot was 6cm and the solvent had moved by 8cm. Calculate the Rf value.