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Hydrogen chloride and water are simple molecular, covalent compounds - Edexcel - GCSE Chemistry - Question 3 - 2017 - Paper 1
Question 3
Hydrogen chloride and water are simple molecular, covalent compounds. (a). The formula of a molecule of water is H₂O. Describe what this formula shows about a molec... show full transcript
Worked Solution & Example Answer:Hydrogen chloride and water are simple molecular, covalent compounds - Edexcel - GCSE Chemistry - Question 3 - 2017 - Paper 1
Step 1
(a) Describe what this formula shows about a molecule of water.
Answer
The formula H₂O indicates that a molecule of water consists of two hydrogen atoms and one oxygen atom. The 'H' stands for hydrogen, while 'O' denotes oxygen. This representation shows the ratio of the atoms in the molecule, confirming that for every one molecule of water, there are two hydrogen atoms bonded to one oxygen atom.
Step 2
(b) Describe what is meant by a covalent bond.
Answer
A covalent bond is formed when two atoms share one or more pairs of electrons. In the case of water, each hydrogen atom shares an electron with the oxygen atom, resulting in a strong bond that holds the molecule together. This sharing of electrons allows the participating atoms to achieve a more stable electronic configuration.
Step 3
(c) Draw a dot and cross diagram of a molecule of hydrogen chloride, HCl.
Answer
In the dot and cross diagram for hydrogen chloride (HCl):
- Represent the hydrogen atom with an 'H' and its single electron as a dot (•).
- Represent the chlorine atom with a 'Cl' and its seven outer shell electrons as crosses (×××××××).
- Draw a circle around both atoms to show the molecular structure. Indicate that they share one pair of electrons, with the dot from hydrogen and one cross from chlorine representing the shared pair.