Chem Blog Week 20

This week, we learned about the mole and it’s used in chemistry. In class, I did an experiment with my group. The goal was to compare the mass of 1 item to all the rest. The items were an empty bottle, small brown nails, hexnuts, pennies, screws, washers, bolts, and panel nails. To do the experiment, the first item we measured the mass of was the empty bottle. We found out it was 9.5g, and since all the elements had to stay in bottles, we subtracted 9.5g from all the rest of the total masses to find the masses of the small brown nails, hexnuts, pennies, screws, washers, bolts, and panel nails.

We had to choose one item to compare to all the other objects. Since the small brown nails had the least mass, we decided to compare it to the other items, and we found the ratios of their masses to the small brown nails. The picture above shows the data. The small brown nails had a mass of 1.3g, the hexnuts 18.9g, the pennies 11g, the screws 10g the washers 23.6g, the bolts 7.1g, and the panel nails 4g. The small nails to hexnuts were 1 to 14.5, small nails to panel nails were 1 to 5.46, the small nails to pennies were 1 to 8.3, the small nails to washers were 1 to 18.15, the small nails to screws were 1 to 7.69, and the small nails to bolts were 1 to 5.46. Therefore, I have concluded that small nails were the smallest, and the washers have the largest mass since the ratio between small nails and washers was the greatest.

I still felt unsure, though, on particles and how to count them. How can I represent them in a group? This question was then answered as I learned in class that for every mole, there are 6*10^23 particles. Thus, the word mole is the collective group of particles.

We found out that like this lab, this was how scientists found the atomic masses of the elements. They compared it to hydrogen, which has the smallest atomic mass, to all the rest. Also, the overall concept I learned from this was that there can be some way of calling 6 pieces of hardware to 1 collective group (e.g. 1 dozen=12 items). 1 dozen would be the collective group. So, we came up with a collective group name for the 6 hardware pieces: the Quinn. Therefore, proportionally speaking, for every Quinn, there are 6 hardware pieces and vice versa.

With this information we are able to plug in information like an algebraic equation and easily find an answer!

Overall this week feel okay with what I learned. I understand the concept, however, I am having a little trouble with the calculating of moles. I should be able to understand it with some practice.

Chem Blog Week 19

This week, our studies were mostly based off the following experiment of chemically mixing zinc and hydrogen chloride and finding its product and its volume so I wanted to describe the process of what we did thoroughly for full understanding.

In the experiment we used a known procedure to find the volume and type of the reactant. We were told to fill a bottle all the way with water while filling the trough with water. Then, mix the zinc and the hydrogen chloride together. But, we had to seal the beaker quickly so that the gas wouldn't escape. The gas goes through an opening inside the trough by a tube connecting the two. So, to collect the product, you should fill a bottle with water and tip it over right side using a lens to prevent spilling while removing the lens afterward. (I have become a pro at this art!) Then, combine the zinc and hydrogen chloride to react. When the glass bottle once filled with water is now full with gas we used the lens again to remove the bottle.

Now, with the gas in the bottle, my group and I can test its chemical properties to determine what the gas is. We previously learned that Hydrogen is flammable and oxygen is combustible. To determine if the gas had these properties, we lit a match to test for combustibility and flammability. Once we put the match in the container, the flame got brighter. Therefore, the gas was flammable. When the match got in contact with the gas, a popping sound was made. Therefore, the gas was combustible. We also had to find the density of the gas to help determine what it is. Subtract the mass of the beaker from the total mass. Then, find the volume of the gas by looking at the bottle. If there is any water in the bottle, this shows the amount of space it takes up. Then, you divide the mass of the reactant by the volume in which it took up the bottle to find the density.

To measure the zinc, we just put it on a measuring scale to calculate its mass. Then, to find out the mass of hydrogen chloride, I figured that in order to do so, we must find out the change in mass when comparing the beaker's mass to the mass of the beaker and the hydrogen chloride in it. Then, I subtracted the mass of the beaker with the total mass, therefore, to find the mass of hydrogen chloride.

By finding the masses of all these variables, we figured this would be the best way to find out the total mass after the zinc and the hydrogen chloride are chemically combined together is by adding the masses of hydrogen chloride and zinc before they were combined. I assumed that since hydrogen or chlorine would escape from the system, the mass would have to decrease. With these results, we concluded that since the gas was combustible and flammable, it had both oxygen and hydrogen. But we asked the question “Where did the zinc and the chloride go?” And how did the oxygen get into the bottle? We conclude that since the air has oxygen, and since it is diatomic, it combined with hydrogen to form water. It makes sense because the bottle had condensation in it.

With this experiment it should be easy to understand the lessons ahead and I am very excited about it!

Chem Blog Week 18

This week, We learned about the concepts of Dalton's theory.

 

On Monday, our class did a simulation on Dalton's theory in the computer game. The first part of the game (Priestley)  consisted of burning calx. As 7.39g of the 100g calx was burned, only 92.61g remained. We then had to use 200g of calx. With conservation of mass it would be understandable that the mass would be two times as much than the product from the first trial. The change in mass was 14.78g from the 200g calx. Therefore, depending on the mass of a substance burning, it loses mass at a proportional rate. We also had to find the volume of gas produced after burning the calx. I noticed that more mass was burned, the more volume the calx would be surrounded in. Using the 100g, the volume of gas came out to be 5.171L, and then using the 200g, the volume of gas came out to be 10.34L. So since there is only half of the mass of calx left, the volume doubled. Also, the volume of gas changed at a proportional rate to the rate at which the mass of calx changed. With this simulation, we learn that all chemical reactions occur in a fixed ratio.

The next experiment was the Lavoisier portion. This is where the phlogiston and the oxygen were tested at burned at different rates to see how they would change in mass or volume. First, 1/3 of the phlogiston was burned. To begin with, both started out with volumes of 6L and they were both in separate beakers , which had tubes connecting to a center beaker, which is where the gas would go. As the oxygen and phlogiston burned, 5L for both were left. Next, as 2/3 of the phlogiston were burned, 4 L for both oxygen and phlogiston were left. But then, when all the phlogiston was burned, only half of the phlogiston was used up so that 3L of oxygen were left. This would mean that the phlogiston burned quicker, two times to be exact. We were then later told that they renamed phlogiston to hydrogen simply meaning “water maker”.

 

Lastly, we worked on the Diamond and Charcoal lab. We started out with 0.20g of charcoal and diamond and kept the mass of oxygen at 1.06g and volume at 0.74L constant (charcoal and diamond were tested individually). The mass of the oxygen decreased from 1.06g to 0.73g as the subtracted amount went to the 0.20g of charcoal, thus increasing the mass of charcoal to 0.53g. Next, 0.40g of charcoal was tested with the same volume of gas (0.74L). Then, the mass of gas decreased from 1.06g to 0g and the volume dropped from 0.74L to 0L. Therefore, with twice the mass, the rate at which volume dropped doubled, hence the rate at which charcoal's mass increased. It was interesting to see that while charcoal and diamond look so different, they do still share chemical properties. I learned that they were related because of Jimmy Neutron! In conclusion, when something is taken away it is always somewhere else due to it being in a closed system and that chemical reactions occur at a fixed ratio.

We later on in the week focused on the things we learned in class on Monday and we had an assessment on Friday. I am not sure how I did, but I know I struggled in some areas that I missed that week.