In the reaction 2H2 + O2 → 2H2O, how many grams of oxygen are required to react

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Question: In the reaction 2H2 + O2 → 2H2O, how many grams of oxygen are required to react with 4 grams of hydrogen?

Options:

Correct Answer: 8 g

Solution:

First, calculate moles of H2: 4 g / 2 g/mol = 2 moles. From the reaction, 2 moles of H2 require 1 mole of O2. Therefore, 2 moles of O2 = 32 g.

In the reaction 2H2 + O2 → 2H2O, how many grams of oxygen are required to react with 4 grams of hydrogen?

In the reaction 2H2 + O2 → 2H2O, how many grams of oxygen are required to react with 4 grams of hydrogen?

Step 1: Find the molar mass of hydrogen (H2). The molar mass of H is about 1 g/mol, so H2 is 2 g/mol.
Step 2: Calculate the number of moles of hydrogen in 4 grams. Use the formula: moles = mass / molar mass. So, moles of H2 = 4 g / 2 g/mol = 2 moles.
Step 3: Look at the balanced chemical equation: 2H2 + O2 → 2H2O. This tells us that 2 moles of H2 react with 1 mole of O2.
Step 4: Since we have 2 moles of H2, we need half that amount of O2. So, 2 moles of H2 require 1 mole of O2.
Step 5: Find the molar mass of oxygen (O2). The molar mass of O is about 16 g/mol, so O2 is 32 g/mol.
Step 6: Calculate the mass of oxygen needed. Since we need 1 mole of O2, the mass of O2 = 1 mole * 32 g/mol = 32 grams.

Stoichiometry – Understanding the quantitative relationships between reactants and products in a chemical reaction.
Mole Calculation – Calculating the number of moles from mass using molar mass.
Mass-Mole Relationships – Converting moles of one substance to moles of another using the coefficients from the balanced equation.