HeyEveryone... This week in Chemistry I learnedabout Stoichiometry. But I don\'t
ID: 691019 • Letter: H
Question
HeyEveryone... This week in Chemistry I learnedabout Stoichiometry. But I don't understand it (noteven a little) so I'm asking anyone for help. Any notes about the subjectwould be so HELPFUL and I would appreciate italot. but here's a sample problem orwhat I'm doing in class and well I hope someone will answer it withsome helpful notes and steps.Thank You.Solid silicon dioxide,often called silica,reacts with hydrofluoricacid (HF) solution to produce the gas silicon tetrafluoride andwater. 1.) write a chemical equation then show the newbalanced chemical equation and explain how you would use them instoichiometric calculations. 2.)List Three mole ratios and explain how you woulduse them in stoichiometric calculations. Any Help Would Be So Helpful,Thank You... [[Amazing Amanda]] HeyEveryone... This week in Chemistry I learnedabout Stoichiometry. But I don't understand it (noteven a little) so I'm asking anyone for help. Any notes about the subjectwould be so HELPFUL and I would appreciate italot. but here's a sample problem orwhat I'm doing in class and well I hope someone will answer it withsome helpful notes and steps.Thank You.
Solid silicon dioxide,often called silica,reacts with hydrofluoricacid (HF) solution to produce the gas silicon tetrafluoride andwater. 1.) write a chemical equation then show the newbalanced chemical equation and explain how you would use them instoichiometric calculations. 2.)List Three mole ratios and explain how you woulduse them in stoichiometric calculations. Any Help Would Be So Helpful,Thank You... [[Amazing Amanda]]
Explanation / Answer
Silicon dioxide is written as SiO2, hydrofluoric acid isHF, silicon tetrafluoride is SiF4, and water isH2O. This gives us the (unbalanced) reaction: SiO2 + HF -> SiF4 + H2O Now, the #1 rule is that there needs to be the same number of eachtype of atom on each side of the chemical equation. So, takea look at one of the molecules anywhere in the equation. I'llpick SiO2. There is a total of 1 Si atom on theleft side of the equation. Is there 1 Si on the right? Yes! So, we're good so far. Looking at the same molecule, we see that there are 2 O's on theleft side of the equation (there are none with the HF). Onceagain, we ask if there are two O's on the right as well. Nope! There is only one, so we'll write a two in frontH2O: SiO2 + HF -> SiF4 + 2H2O Now, that 2 applies to both the the H2 as well as the O,a bit like how the a in the expression a*(b + c) applies to both band c. The difference between H2 and 2H is thatH2 implies that two H's are chemically bonded, but 2Hjust mean that two H's have been produced. So, we have two O atoms on each side of the equation, but noticethat writing a 2 in front of H2O has given us 4 H's onthe right side of the equation (two H2 atoms has 4 Hatoms total)! Since there is only one H on the left, we'dbetter write in another stoichiometric coefficient in front of theHF - 4: SiO2 + 4HF -> SiF4 + 2H2O Now we have another side effect: by adding the 4 in front of theHF, we have 4 F's too. But, on the other side of theequation, there is an F4, so we're done! Lookagain through the four types of atoms in the equation and you'llsee that there are the same number of each type of atom on eachside of the equation. This equation isbalanced. These coefficients are useful when doing calculations because theytell us the mole ratio of each type of moleculeinvolved in the reaction, similar to that of a recipe. So, ifyou want to have a reaction involving 3 moles of SiO2,you'll know that you also need 12 moles of HF. Your book alsomight tell you a bit about what these coefficients are goodfor. They come in handy for many things, but I'm not in yourclass, so I'm not quite sure what specific things you need. An example of a mole ratio from the equation I just balanced wouldbe 1 SiO2 / 4 HF, which means for every mole ofSiO2, there should be 4 moles of HF. I'm sure youcan come up with more from our chemical equation. Hope that helps! If that didn't make sense, feel free privatemessage me about what you don't get.