OCR A-Level Chemistry: Module 2 - Foundations in Chemistry
This flashcard set covers key definitions and concepts related to atomic structure, including isotopes, relative atomic and isotopic mass, and experimental techniques like mass spectrometry. It’s designed for quick recall of foundational chemistry terms and principles.
Define relative isotopic mass (2)
Mass of the isotope compared to 1/12th of the mass of a carbon 12
Key Terms
Define relative isotopic mass (2)
Mass of the isotope compared to 1/12th of the mass of a carbon 12
Define isotopes (1)
Atoms with the same number of protons but a different number of neutrons
Explain why isotopes have the same chemical properties (1)
Same number of electrons in the outer shell
Define relative atomic mass (3)
The weighted mean mass of an atom relative to 1/12th the mass of one atom of carbon 12
How could the fraction of the isotopes of carbon be found experimentally? (1)
Mass spectrometry
Explain what is meant by a salt (1)
When the H+ in an acid is replaced by a metal ion
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| Term | Definition |
|---|---|
Define relative isotopic mass (2) | Mass of the isotope compared to 1/12th of the mass of a carbon 12 |
Define isotopes (1) | Atoms with the same number of protons but a different number of neutrons |
Explain why isotopes have the same chemical properties (1) | Same number of electrons in the outer shell |
Define relative atomic mass (3) | The weighted mean mass of an atom relative to 1/12th the mass of one atom of carbon 12 |
How could the fraction of the isotopes of carbon be found experimentally? (1) | Mass spectrometry |
Explain what is meant by a salt (1) | When the H+ in an acid is replaced by a metal ion |
What term is given to the .n H2O part of a formula? (1) | Waters of crystallisation |
What calcium compound is formed when calcium oxide reacts with water? (1) | Calcium hydroxide |
What calcium compound is formed when calcium oxide reacts with nitric acid? (1) | Calcium nitrate |
How do old samples of magnesium oxide become contaminated with magnesium carbonate? (1) | MgO has reacted with CO2 |
A student adds an excess of HCl to magnesium oxide and magnesium carbonate, state two observations that would be made (2) | Solid dissolves Effervescence |
Define an acid (1) | A proton donor |
How can CaCO3 be used to combat excess stomach acid? Use an equation (2) |
CaCO3 + 2HCl -> CaCl2 + H2O + CO2 |
State an important use of ammonium sulphate (1) | Fertiliser |
State a large-scale use of ammonia (1) | Manufacture of explosives |
Use oxidation numbers to explain why the reaction involves both oxidation and reduction (algebraically) (3) | X: oxidation number goes up |
Explain, in terms of electrons, what is meant by oxidation (1) | Loss of electrons |
What is meant by the term mole? (1) | Amount of substance that has the same number of particles as there are atoms in 12g of carbon 12 |
What is a common use of NaClO? (1) | Bleach |
Define empirical formula (1) | Simples whole number ratio of atoms |
After Ca has fully reacted with HCl, upon adding more Ca, a reaction still takes place, why? (3) | Ca has reacted with water Ca + 2H2O -> Ca(OH)2 + H2 |
Explain what is meant by molecular formula (1) | Number and type of atoms making up a molecule |
What is meant by ionic bonding? (1) | Electrostatic attraction between oppositely charged ions |
Predict the bond angle in an F2O molecule and explain (3) | 104.5 |
Describe and explain two anomalous properties of water from hydrogen bonding (4) | Liquid H2O is more dense than solid |
Magnesium melting point: 650°C | Mg has a giant structure |
Describe the bonding and structure in graphite | Explain why graphite is a good conductor, a soft material and a very high melting point (5) | Giant covalent lattice Arranged in layers Good conductor - mobile electrons High melting point - covalent bonds have to be broken Soft - weak forces between the layers |
What is meant by a covalent bond? (1) | A shared pair of electrons |
Name the shape of the ammonia molecule and why ammonia has this shape and a bond angle of 107° (3) | Pyramidal |
Why does ammonium chloride not conduct electricity when solid but does when dissolved in water? (2) | Ions cannot move in a solid | Ions can move in solution |
What is meant by metallic bonding? (2) | Electrostatic attraction between the delocalised electrons and the positive ions |
Why does H2S have a much lower boiling point than H2O? (2) | No hydrogen bonding | Weaker intermolecular forces |
What is meant by hydrogen bonding? (1) | Interaction between lone pair of F, N or O and a H in a neighbouring molecule |
Explain electronegativity (2) | Attraction of an atom for electrons in a covalent bond |
Why do O-H and N-H bonds have dipoles? (1) | Oxygen and nitrogen are more electronegative than hydrogen |
Why does a water molecule have a different shape to a carbon dioxide molecule? (2) | Electron pairs repel |
Why is water a polar molecule, but CO2 is not? | CO2 is symmetrical | In CO2, dipoles cancel |