Is there any formula for this kind of chemistry problem?

[stanton]

I am suffering from this kind of chemistry problems. I think I will have bunch of these in my exam. But I can't understand this kind of problem's solutions. If you know any formula or information about this, please help.

How many grams of fluorine gas must react to give 9.26 g of sulfur hexafluoride?
What mass of calcium chloride is required to react completely with 5.00 g of sodium phosphate?
How many grams of oxygen gas must react to give 6.85 g of calcium oxide?
type of problem: how many [gram/mole] must [react/be needed] to [produce/give] x gram of p?

The official state of this problem is called [calculate amounts of reactants for a reaction in grams or moles]

You do not have to answer to these problems. But if you can give me some procedures about how the answer can be derived, I would appreciate it, because I want to know kind of formula, equation to plug values in it.

What I tried is to divide the weight I am given with the formula weight of something...can't go further. Please help.

 

[Sakha]

I will try to explain it to you with a pretty simple equation.
2H₂+O₂=2H₂O
By knowing the balanced chemical equation, you know the mole proportion between the reactants and the products. In our example, for each mole of O₂ you get twice that amount of H₂O moles.

Everything has to be calculated in moles, so if the problem gives you the mass of a reactant or product, you simply convert mass to moles using the molar mass of the compound or viceversa.

 

[Borek]

about solving stoichiometry problems

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