Question detail
A reaction between magnesium (Mg) and oxygen (O2) produces magnesium oxide (MgO). If 12 g of magnesium reacts with excess oxygen, calculate the number of moles of magnesium used in the reaction.
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
Question
Type
exam_style
Style
Topic
Use of amount of substance in relation to masses of pure substances
Question
A reaction between magnesium (Mg) and oxygen (O2) produces magnesium oxide (MgO). If 12 g of magnesium reacts with excess oxygen, calculate the number of moles of magnesium used in the reaction.
Answer
0.5 mol
Explanation
This question tests the ability to calculate moles from mass using the relative formula mass of magnesium. The calculation shows understanding of the relationship between mass and moles.
Common mistake
Confusing Mass Ratios with Mole Ratios
Students often confuse mass ratios with mole ratios when balancing equations, leading to incorrect calculations.
Always ensure you are using the mole ratios derived from the coefficients of the balanced equation, not the masses of the reactants or products.
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