Empirical Formula of Magnesium Oxide transcript

all chemistry students today we're going to be performing our empirical formula of magnesium oxide lab the purpose of this experiment is to identify a molecule formula after a chemical reaction has occurred let's get started okay so to start this experiment we're going to heat a clean dry crucible and it's cover on a clay triangle that's supported by a ring stand we're going to be using a Bunsen burner in a direct flame we're going to heat it for about five minutes we'll get our crucible set up and our cover on and then we're gonna go ahead and start our light our Bunsen burner we'll let that heat for five minutes so our crucible and cover have been heating for five minutes now so we're gonna go ahead and turn off the flame and we're going to allow our crucible and cover to cool and we're going to leave it in the crucible we're gonna leave the Kris bowl and cover in the clay triangle here to cool you oK we've allowed our crucible and cover to cool so now we're going to weigh the empty dry crucible and the cover on a digital balance okay so the weight of our dry cover is 16.8 nine four zero grams okay so next we're going to obtain a piece of magnesium ribbon we have our magnesium ribbon here okay so our magnesium ribbon is nice and shiny so we do not need to polish it with steel wool to remove any oxide coating so we're going to fold the magnesium ribbon good idea is to wrap it around a pencil so here's our folded magnesium ribbon and place it in our crucible now we're going to weigh our crucible cover and magnesium ribbon together okay so the mass of our crucible our crucible cover and the magnesium ribbon is 17-point oh three nine six grams okay so for this next part we're going to start heating the crucible with the magnesium so we have the crucible with the magnesium inside I'm set it on a clay triangle we're going to start heating with the crucible cover off and so as it starts heating as soon as the magnesium catches fire I'm gonna put the crucible cover on continue heating for about a minute or so then I'll remove the crucible cover and as if it catches fire again I will put the crucible cover back on continue heating and we will repeat that process until the magnesium no longer catches fire when the crucible cover has been removed I'm going to light our Bunsen burners we have our crucible cover ready with the crucible tongs and now we'll heat until our magnesium ignites hope so its igniting I don't know if you could see the light coming out of there or not but the magnesium was lighting so now we're going to let it go for about a minute or so before we remove the cover so let's remove the cover and see if it continues to ignite still igniting put the cover back on check again still igniting hey let's check again we're still igniting a little bit check again it's annoying just a little bit inside of the crucible let it continue going okay let's check our crucible again with the cover so at this point it appears that our magnesium is no longer igniting so we're going to cover the crucible and heat with the Bunsen burner for an additional five minutes so let this heat for five minutes okay at this point our crucible has been heating for five minutes and the bottom of our crucible has been red-hot so we're going to turn the burner off and let the crucible cool until it is just barely warm to the touch so I'll let this cool okay so our crucible is now just warm to the touch here so at this point we're not going to need the crucible cover so I'm just going to remove it and set it off to the side put our crucible back on the clay triangle and now we're going to add ten drops ci water to wet the entire surface of the sample not just one spot so 10 drops you those are ten drops now we're going to turn and barn burner back on and we're going to warm the crucible with the damp sample inside for about a minute or so you we're going to let this warm for about a minute I don't know if you can hear but the water is being driven off okay so we've warmed gently for about a minute we're gonna turn the flame up just a little bit and heat moderately for about ten minutes and again we don't need the cover for this part of the heating we just want to eat moderately the bottom of the crucible does not need to become red-hot in this part of the experiment we'll let this go for about 10 minutes or so okay we've heated the crucible for about 10 minutes so now we're going to turn off the Bunsen burner we're gonna let the crucible cool until barely warm to the touch okay so at this point we've allowed our crucible and cover and the magnesium oxide inside to cool until just warm to the touch and you can see we have our crucible or cover and our magnesium oxide is inside the crucible so now we're going to take all three of these the crucible the magnesium oxide and the cover and we're going to mask them on our analytical balance you okay so the total mass of the crucible and magnesium oxide and the crucible cover is 17 point 1 3 3 8 grams so you can you now can perform the necessary calculations to determine the empirical formula of magnesium oxide for trial number one we're going to go ahead and do a quick trial number two okay so for trial number two I've already gone ahead and heated another crucible and lid for five minutes and allowed it to cool to room temperature now I'm going to mask that crucible and lid so the mass of the crucible and lid for trial number two is 18 point zero one zero three grams okay we're going to take another strip of magnesium for trial number two under pencil like so and then add it to our crucible okay we're now going to the mass of our crucible our crucible cover and our magnesium ribbon for trial number two so our mass of our crucible a crucible cover and our magnesium ribbon for trial number two eighteen point one five five nine grams okay so we're gonna perform trial number two I've got the crucible and the magnesium ribbon in the clay triangle and we're going to leave the crucible cover off for the moment I'm going to turn on the Bunsen burner and we're gonna get the crucible heating and then as soon as the magnesium starts to ignite I will cover the crucible with the crucible cover for about one minute and then I will remove it allow it to ignite again and then cover and repeat that process until upon removal of the crucible cover the magnesium no longer ignites so let's go ahead and start that process so we're eating until our magnesium starts to ignite and once the it starts to ignite we will cover with the crucible cover okay so our magnesium is starting to ignite so I'm going to cover with the crucible lid and continue heating for about another minute okay so it's been about a minute I'm going to remove the crucible cover wait for the magnesium to a night ignite again which it is right now and then cover with the crucible cover for about another minute okay so we're gonna repeat this process until the crucible cover once the crucible covers remove the magnesium no longer ignites okay so at this point when we remove the cover the magnesium is no longer igniting so we're gonna go ahead and place the cover back on and heat strongly for an additional 5 minutes make sure that the crucible bottom becomes red-hot you can might already be able to see it's pretty red-hot right now but we'll turn up the flame a little bit and we'll heat for five minutes so we're about one minute into our 5 minutes of strong heating that you should be able to see now that the bottom of our crucible is red-hot that's what we want to see okay at this point it's been five minutes so we're going to turn off the burner and let the crucible cool until it's just barely warm to the touch again let the crucible cool oK we've allowed the crucible to cool until just barely warm to the touch or magnesium oxides inside of there inside the crucible so we don't need the cover for this part of the experiment again I'll - so we're going to take ten drops of di water and wet our sample and make sure that the entire sample gets wet you that's ten drops so now we're going to warm the crucible with the damn sample with a gentle flame for about a minute or so for a minute okay so we've let the damp sample heat for about one minute we're now going to adjust the flame to a moderate heat and heat for 10 minutes we do not need the crucible to become red-hot in this step so we'll let this go for 10 minutes okay so we've let the crucible eat moderately for 10 minutes so we're going to turn off the Bunsen burner and we're going to allow the crucible and a magnesium oxide inside to cool until just warm to the touch okay so we've allowed the crucible to cool until just warm to the touch so now we're going to mask the crucible the magnesium oxide inside and the crucible cover for trial number two okay so the mass of our crucible our crucible cover and our magnesium oxide for trial number two is eighteen point two five zero six grams okay so now that we have all the masses for trial number two you should now be able to perform the necessary calculations to determine the empirical formula of magnesium oxide that concludes this lab thank you for joining me for the empirical formula of magnesium oxide lab