in stoichiometry, after you have balanced the formula, how do you know which substance is the one you use to convert all 4 times to get the wanted reults
You have to work these in mole><mole. Conversion depends if you want mass or volume of gas.
http://www.khanacademy.org/video/stoichiometry?playlist=Chemistry
hey tanks
thanks i meant
After balancing the chemical equation in stoichiometry, you can determine which substance to use for the conversion by identifying the desired quantity or substance you want to calculate. Here's the step-by-step process to determine the conversion factor:
1. Define the Problem: Clearly state what you are trying to find or calculate in terms of moles, grams, or any other unit.
2. Identify the Given Information: Look at the information provided in the question, including the amounts of reactants or products given, as well as any other relevant data.
3. Calculate the Molar Ratios: Use the balanced equation to determine the molar ratios between the known and unknown substances. The coefficients in the balanced equation represent the relative number of moles of each substance involved in the reaction.
4. Choose the Appropriate Conversion Factor: Select the conversion factor that will allow you to cancel out the given units and obtain the desired units.
5. Perform the Calculation: Multiply the given quantity by the conversion factor to obtain the desired quantity or substance.
Here's an example to illustrate the steps:
Question: How many grams of water (H2O) can be produced from 10 grams of hydrogen gas (H2) reacting with excess oxygen gas (O2)?
1. Define the Problem: Calculate the mass of water produced.
2. Given Information: 10 grams of hydrogen gas (H2).
3. Molar Ratios: From the balanced equation:
2H2 + O2 → 2H2O
The molar ratio between hydrogen gas and water is 2:2, or 1:1.
4. Conversion Factor: The conversion factor is 1 mole of H2O/1 mole of H2.
5. Calculation:
10 grams of H2 * (1 mole of H2/2.02 grams) * (1 mole of H2O/1 mole of H2) * (18.02 grams/1 mole of H2O) ≈ 45.0 grams of H2O
So, 10 grams of H2 will produce approximately 45.0 grams of H2O.
By carefully considering the quantities and using the balanced equation, you can determine which substance to use as the conversion factor to obtain the desired result in stoichiometry.