chem blog - mass, volume, and density

      Over this past week, we finished the rest of worksheet #3 and put the answers up on whiteboards, completed worksheet #4 as a class, found the density of a gas through an experiment, and found the thicknesses of two different aluminium foil. These main ideas connect because for each worksheet/experiment, we had to use the concept of mass, volume, and density being related.

Worksheet #3 We completed the rest of this worksheet, which is problems 4 to 8, through whiteboards with our table. Problem 4 showed a graph and a pan balance of substance A and substance B. We first had to find out what would happen if equal masses of A and B were put into the pans. We then had to find out what would happen if equal volumes of A and B were put into the pans. Afterward, we found the slope for A and B and explained the physical meaning of slope for each substance. Then we found the mass and volume of A and B when the other substance was a specific value. We then sketched water's density (1.00 g/mL) on the graph. Finally, we determined wether substance A or B would sink or float when placed in a bucket of water.

Our answers for 4 a-b

Our answers for 4 c-f

Problem 5 gives us an empty graph and a table with substances and their density. We were asked to sketch a graph of mass vs. volume for titanium, copper, and mercury. Problem 6 states that a certain cube measure 2.00 cm on every side. We first had to find the volume of the cube in both cm³ and mL. Then we found the mass of the lead, nickel. and zinc cube using the table given in problem 5.

Our answers to 5 and 6

Problem 7 states that Alicia's boyfriend gave her a supposedly 24 carat gold. Alicia found the mass, final volume, and initial volume of the ring. We were asked to find the volume and density of the ring and wether or not Alicia should dump her boyfriend. Problem 8 gives us the meniscus measurement and the measurement of the water level after a solid object was dropped into the graduated cylinder. It also gives us the density of the object. We had to determine the mass of the object.

Our answers for 7 and 8

Worksheet #4 This worksheet focused on applied density problems. We were given the density and either mass or volume of a substance. We then had to calculate either the mass or volume of the substance, depending on what was given. Most of the worksheet was done as a class.

Density of Gas We were given a submerged bottle in a water-filled basin. A tubing end was stuck under the bottle. We then measured about 40 mL of water and poured it into the plastic squeeze bottle. Then we massed the plastic squeeze bottle and cup with Alka-Seltzer. Then we dropped the cup with Alka-Seltzer into the bottle and screwed on the cap with tubing. Afterwards we shook the bottle for about 10 minutes and waited for all the gas to go through the tube. We then marked the water line with pencil and took the submerged bottle out of the water. The volume of the gas was found as we discussed in class. Then we massed the contents of the bottle after the reaction. For my data, the mass before the reaction was 67.848 grams. The mass after was 67.814 grams. The mass of the gas was 0.334 grams. The volume of the gas was 184 mL. We found out that the density of the gas was 0.00181 g/mL. After everyone completed the experiment, we compared our data as a class.

Submerged bottle in water-filled basin

shaking the bottle with Alka-Seltzer in it

Gas going through the tube into the submerged bottle

Measuring the volume of the gas

Class data for this experiment

Aluminium Foil We were given two supposedly equal sheets of two different brands of aluminium and the density of aluminium (2.7 g/cm³). We first found the mass of both sheets. Then we found the volumes by dividing density from mass. We then measured the length and width of the sheets. Afterwards, we calculated the thickness of the sheets by dividing the volume by the multiplicative of the length and width values. Our mass and volume for the first sheet was 2.343 grams and 0.8678 cm³. Our mass and volume for the second sheet was 3.082 grams and 1.141 cm³. The thickness for the first sheet was 0.0016 cm. The thickness for the second sheet was 0.0024 cm.

Whiteboard of our results

      We came to know and understand the ideas this week by comparing answers and data as a class and discussing what occurred. I don't have any questions relating to what we learned this week. My participation this week was pretty good but I got distracted a couple times. I would rate my understanding of all the ideas from this class a 10 because I'm sure I know and understand all the concepts that we covered this past week. I need to work on not being distracted by my friends as often.