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The arrangement of carbon atoms in diamond is shown - Edexcel - GCSE Chemistry - Question 6 - 2015 - Paper 1
Question 6
The arrangement of carbon atoms in diamond is shown. Explain why diamond has a very high melting point. (b) (i) Calculate the percentage by mass of calcium in calc... show full transcript
Worked Solution & Example Answer:The arrangement of carbon atoms in diamond is shown - Edexcel - GCSE Chemistry - Question 6 - 2015 - Paper 1
Step 1
Explain why diamond has a very high melting point.
Answer
Diamond has a very high melting point due to its strong covalent bonding structure. Each carbon atom in diamond is tetrahedrally bonded to four other carbon atoms, forming a rigid three-dimensional lattice. This arrangement requires a significant amount of energy to break the bonds, resulting in high melting temperatures.
Step 2
Calculate the percentage by mass of calcium in calcium chloride, CaCl₂.
Answer
To find the percentage by mass of calcium in calcium chloride (CaCl₂), we first find the relative formula mass of CaCl₂:
- The atomic mass of calcium (Ca) = 40 g/mol
- The atomic mass of chlorine (Cl) = 35.5 g/mol
- Hence, for CaCl₂:
Next, we calculate the percentage by mass of calcium:
Step 3
Which row of the table correctly shows the solubility of calcium chloride and barium sulfate in water?
Answer
The correct row that shows the solubility of calcium chloride and barium sulfate in water is A:
- Calcium chloride: soluble
- Barium sulfate: insoluble
Thus, a cross (✗) should be placed in: A.
Step 4
Use the diagram to describe the structure of a metal and to explain why metals are malleable and conduct electricity.
Answer
The structure of a metal consists of a lattice of positively charged metal ions surrounded by a sea of delocalized electrons. This arrangement allows the layers of atoms to slide over one another without breaking metallic bonds, making metals malleable.
Additionally, the presence of free-moving electrons enables metals to conduct electricity as these electrons can carry an electric charge throughout the metal.