Photo AI
Hydrogen burns in air at a temperature well above 100°C to form water - Edexcel - GCSE Chemistry - Question 10 - 2018 - Paper 1
Question 10
Hydrogen burns in air at a temperature well above 100°C to form water. (i) The boiling points of hydrogen and water are shown in Figure 15. Use this information to... show full transcript
Worked Solution & Example Answer:Hydrogen burns in air at a temperature well above 100°C to form water - Edexcel - GCSE Chemistry - Question 10 - 2018 - Paper 1
Step 1
Use this information to add the missing state symbols to the equation for the reaction taking place as the hydrogen burns.
Answer
The correct equation with state symbols is:
In this equation, hydrogen is in the gaseous state (g) and water is in the liquid state (l) at temperatures above 100°C.
Step 2
State how the equation shows that the atom economy is 100%.
Answer
The atom economy is calculated by the formula:
ext{Atom Economy} = rac{ ext{mass of useful products}}{ ext{total mass of reactants}} imes 100In the equation, all reactant atoms are converted into a single product, water (H₂O), with no by-products or wasted atoms. Hence, the atom economy is 100%, since the mass of the useful product equals the total mass of reactants used in the reaction.
Step 3
Calculate the atom economy for the production of lead in this reaction.
Answer
First, we identify the relative formula masses involved:
- Mass of reactants:
- Mass of useful products:
Therefore, the atom economy is:
ext{Atom Economy} = rac{458}{458} imes 100 = 100 ext{%}Thus, the atom economy for the reaction is 100%, indicating that all the reactants are fully utilized for the production of lead.