Consider the reaction,

CH4(g) + 2 O2(g) => CO2(g) + 2 H2O(g).
How many grams of H2O(g) will be made by the reaction of 17 moles of CH4(g) with 7 moles of O2(g)?

This is a limiting reagent problem. How do I know that. Because BOTH reactants are given. Basically, what we do is work two simple stoichiometry problems, identify the limiting reagent as the one producing the smaller amount of product.

CH4(g) + 2 O2(g) => CO2(g) + 2 H2O(g).

First CH4: Using the coefficients in the balanced equation, convert 17 moles CH4 to moles H2O.
17 moles CH4 x (2 moles H2O/1 mole CH4) = 34 mols H2O
Next O2: Same process.
7 mols O2 x (2 moles H2O/2 mols O2) = 7 moles H2O.
Obviously both answers can be right which means one of them is wrong. The correct answer in limiting reagent problems is ALWAYS the smaller value; therefore, the reaction will produce 7 moles H2O and O2 is the limiting reagent.
Now convert 7 moles H2O to grams.
g = mols x molar mass.

thanks..now I know how to do this kind of problem...you rock!

To find out how many grams of H2O(g) will be produced in the given reaction, we need to use the stoichiometry of the reaction.

Step 1: Write down the balanced equation for the reaction.

CH4(g) + 2 O2(g) => CO2(g) + 2 H2O(g)

Step 2: Determine the mole ratio between CH4 and H2O in the balanced equation.

From the balanced equation, we can see that for every 1 mole of CH4, 2 moles of H2O are produced. This gives us a mole ratio of CH4 to H2O as 1:2.

Step 3: Calculate the moles of H2O produced.

Given:
Moles of CH4(g) = 17 moles
Moles of O2(g) = 7 moles

Since the mole ratio between CH4 and H2O is 1:2, we can use the given moles of CH4 to calculate the moles of H2O produced.

Moles of H2O = 2 * Moles of CH4

Moles of H2O = 2 * 17 moles

Moles of H2O = 34 moles

Step 4: Convert moles of H2O to grams.

To convert moles of H2O to grams, we need to use the molar mass of water (H2O), which is 18.015 g/mol.

Mass of H2O = Moles of H2O * Molar mass of H2O

Mass of H2O = 34 moles * 18.015 g/mol

Mass of H2O = 612.51 g

Therefore, 612.51 grams of H2O will be produced by the reaction of 17 moles of CH4(g) with 7 moles of O2(g).

To find the number of grams of H2O(g) produced, follow these steps:

Step 1: Start with the given number of moles of CH4(g) and O2(g).

Given:
Moles of CH4(g) = 17 mol
Moles of O2(g) = 7 mol

Step 2: Use the balanced chemical equation to find the mole ratio between CH4(g) and H2O(g).

From the balanced equation:
1 mole of CH4(g) produces 2 moles of H2O(g).

Step 3: Calculate the number of moles of H2O(g) produced by multiplying the moles of CH4(g) by the mole ratio.

Moles of H2O(g) produced = Moles of CH4(g) × Mole ratio
= 17 mol × (2 mol H2O(g) / 1 mol CH4(g))
= 34 mol H2O(g)

Step 4: Convert the moles of H2O(g) to grams using the molar mass of water (H2O).

Molar mass of H2O = 2 g/mol (hydrogen) + 16 g/mol (oxygen)
= 18 g/mol

Grams of H2O(g) produced = Moles of H2O(g) × Molar mass of H2O
= 34 mol × 18 g/mol
= 612 g

Therefore, 612 grams of H2O(g) will be produced by the reaction of 17 moles of CH4(g) with 7 moles of O2(g).