Lab #2 Determination of Density
Britney Williams
Chemistry 121
Dr. Yu
1/29/13

Purpose: To determine the densities of aluminum and zinc cylinders Density is the relationship between the mass of an object and its volume. Sometimes density can be easy to sense. If two objects have exactly the same shape and size, the denser one may feel heavier. If their densities are close together, it can be hard to tell the difference. It gets really tough if you are dealing with materials that have very different sizes or very different shapes. The only way to decide the density of an object is to measure its mass and its volume, then divide. Ex. Density= Mass/Volume Procedure:

For Aluminum:
1. Weigh the aluminum cylinders individually on the analytical balance to the nearest 0.0001g and record the weights 2. With a vernier caliper, measure the diameter of each cylinder to the nearest 0.01cm and record 3. Again, using the vernier caliper, measure the length of each cylinder to the nearest 0.01cm and record 4. Compute the volume of each cylinder by using the formula V= (3.14d2h)/4 For Zinc:

1. Weigh the zinc cylinders individually on the top loading balance to the nearest 0.01g, and record the weights 2. Place enough water in a 100mL graduated cylinder to cover the object. Record the volume of water to the nearest 0.1mL by reading the bottom of the meniscus 3. Place the zinc cylinder in the graduated cylinder. Read the new volume and determine the volume for each piece of zinc

Data:
Density of Zinc
Mass#1 104.0168gVolume#1 18mLDensity#1 5.7780g/cm3
Mass#2 92.8178gVolume#2 15mLDensity#2 6.1876g/cm3
Mass#3 72.2115gVolume#3 10mLDensity#3 7.2215g/cm3
Mass#4 55.3077gVolume#4 9mLDensity#4 6.1453g/cm3
Mass#5 35.2653gVolume#5 7mLDensity#5 5.0379g/cm3
Average Density 6.079g/cm3
Density of Aluminum
Mass#1 26.48gVolume#1 6.28mLDensity#1 4.22g/cm3
Mass#2 21.50gVolume#2 5.01mLDensity#2...

... Unknown Code: K
General Chemistry Laboratory
September 13, 2013
Experiment 1: Determination of Density
Introduction
The purpose of this experiment was to be able to measure the density of water and an unknown substance with a buret and an analytical balance. The density can be calculated by dividing the mass per volume. It was expressed in grams per cubic centimeters, or in this case, grams per milliliters.Density is a very important property that identifies the pure substance being measured without knowing what it is at a given temperature. The temperature is extremely important since it determines the state of the substance being used. Normally, substances expand as the temperature increases making them less dense. So, gases are less dense than liquids and liquids are less dense than solids. But in water, which is measured in this experiment, the solid state is less dense than the liquid state. This is because of the ice crystal structure the molecules form making them occupy more space than the molecules in liquid water. The substance with less density is always on top of the substance with more density.
In addition to measuring the density of water and an unknown substance with a buret and an analytical balance, accuracy and precision will be introduced which is determined by all the data acquired in the data tables.
Experimental
The...

...Title of the Experiment: determination of densities
Introduction
The density of a sample of matter represents the mass contained within a unit volume of space in the sample. For most samples, a unit volume means 1.0 ml. The units of density, therefore, are quoted in terms of grams per milliliter (g/ml) or grams per cubic centimeter (g/cm3) for most solid and liquid samples of matter.
Density is often used as a point of identification in the determination of an unknown substance. The density of the unknown might be used to distinguish the unknown from a list of known substances. It is very unlikely for two substances to have the same density, and when coupled with boiling point and melting point it adds even more validity to the identity of the substance.
Density can also be used to determine the concentration of solutions in certain instances. When a substance is dissolved in water, the density of the solution will be different from that of the pure water itself. Handbooks list detailed information about the densities of solutions as a function of their composition (typically, in terms of percent substance in the solution). If a sample is known to contain only a single substance, the density of the solution can be measured experimentally, and then the handbook can be consulted to determine what...

...Experiment #2 “DensityDeterminations” Report
The objective for experiment #2 was “to determine densities of objects/salt solutions with different concentrations of salt, to see how density changes as a function of concentration.” In experiment #2, part II, calculations of Density of NaCL solutions were made from 0%-25% NaCL concentration. My hypothesis was that as the % increased, so would the density, because adding weight would increase the density of each solution. The density calculations in part II, were precise and accurate within + 0.03 g/cm^3. The results for this experiment prove that as you increase % of NaCL, the density increases also because of the weight of NaCL is increased. Graph #1 shows that as the %NaCL increased so did the density, therefore proving the accuracy and precision of part II calculations. In part III, of the experiment, the density of regular shaped objects, were calculated based on volume measured method and water displacement method. My hypothesis for this part of the experiment was that volume measured method would be more accurate because water displacement method contains too many random errors. The density calculations of volume measured for part III were both more precise and more accurate within a standard deviation of + 0.06 g/cm^3, where water displacement method...

...Table 1: Density based on dimensional analysis
Trial 1 Trial 2 Trial 3 Units
Mass of sample 70.5466 70.5467 70.5465 g
Dimensions of sample Length 4.98 4.98 4.99 cm
Width 1.21 1.22 1.21 cm
Height 1.21 1.22 1.22 cm
Volum of sample 7.29 7.41 7.37 cm^3
Density of sample (based on dimensional analysis) 9.68 9.52 9.57 g/cm^3
Table 2: Density based on the displacement of water
Trial 1 Trial 2 Trial 3 Units
Mass of sample 70.5467 70.5465 70.5466 g
Final volume of the water in the buret (Vf) 29.83 13.11 25.51 ml
Initial volume of the water in the buret (Vo) 14.62 2.61 13.18 ml
Volume of the water dispensed from the buret (Vb=Vf-Vo) 15.21 10.50 12.33 ml
Volume of water level on graduated cylinder: Vgc 23.5 19.2 19.8 ml
Volume of sample 8.29 8.70 7.47 cm3
Density of sample 8.50 8.11 9.44 g/cm^3
2. CALCULATIONS
a. Relative Percent Error = IAbsolute ErrorI/True Value X 100%
IAbsolute ErrorI = ITrue Value - Measured ValueI
The Measured Value in my experiment based on table 2 is [(8.50+8.11+9.44)/3]= 8.68 g/cm^3
The True Value is 8.94 g/mL
Absolute Error = 8.94 - 8.68 = 0.26
Relative Percent Error = (0.26/8.94)x100=2.91 Using the correct number of significant figures,
gives us the answer: 3%
b. Density of metal bar using dimensional analysis
D = Mass/Volume (g/cm^3)
V = LxWxH = 4.98x1.21x1.21 =...

...Lab Report
Question- Why do few objects float in water where as others sink?
Hypothesis- I think the objects that have a greater density than water will sink. So whichever object has a density more than 1g/cm³ will sink in water. This is known as relative density where the density of the substance is compared to the density of water. Hence, the object that has a greater mass: volume ratio than water will sink.
Materials-
* 1 measuring cylinder
* 1 rectangular prism
* 1 ball of plasticine
* 1 cylinder
* 1 cube
* 1 micrometer
* 1 vernier calliper
* 1 balance
Variables-
Independent- The object that was used
Dependent- The density of the object
Controlled- The water in the measuring cylinder
Procedure-
1. Get the 4 objects (rectangular prism, ball of plasticine, cylinder, and cube) that you’re going to experiment with.
2. Measure the mass of the rectangular prism by weighing it on the balance. Weigh it three times to get an accurate measurement. Then find the measurements of the length, width, and height using a vernier calliper. Use the formula l× b× h to find the volume. Divide the mass by the volume to get the density.
3. Measure the mass of the plasticine by weighing it on the balance. Weigh it three times to get an accurate measurement. Now fill up the measuring cylinder to a certain level and note it down. Next, drop the...

...Jahzeel Morales
Jessa Arellano
September 19, 2014
Period 4
Lab #1: DensityDeterminations for Solutions
Theory:
The density of a sample of matter is very useful when trying to find the identity of an unknown substance. The units of density are quoted in (g/mL) for liquid samples of matter. For that reason if the volume is known of a liquid, determining its density is easily determined by weighing it accurately.Density can also be used as a tool for finding the concentration of solutions in some cases. The density is different in a substance when a substance is added to a pure liquid to when both the solute and solvent were separate all together.
There are many ways to determine density. This method determined the density of a liquid by weighing a volume in a graduated cylinder. With the volume in milliliters and the mass in grams, density of an unknown substance can be found by using this method.
Purpose:
The purpose of this experiment is to find the concentrations of 2 unknown substances.
Procedures:
1.) Determine the density of solutions known and unknown concentrations.
2.) Make a mass determination for 10.00 mL of each known and unknown solution, using a balance and a graduated cylinder. Record.
3.) Organize data using a table, and construct a graph of the density of your...

...MEASUREMENT OF PHYSICAL PROPERTIES: DENSITY
Introduction
According to the definition Density is the physical property that allows us to compare the mass of substances for a specific volume. In this Lab activity that took place in Deree College, Agia Paraskevi Campus we deal with the density of solids and density of liquids. The main purpose of this experiment is to understand what in reality density means, how we can measure it, how useful it is, what is the difference between density of solids and liquids, if the measurements that we did are been accurate and how we can calculate the percentage errors.
materials
3 different metals
A) copper
B) iron
C) aluminum
- 3 Different liquids
A) Water
B) Olive oil
C) Alcohol
- Balance
- Cylinders of 25ml, 100ml
- Calculator
DATA/RESULTS
In this Lab activity we saw the differences between the density of solids and the density of liquids.
Firstly we obtained three different solids a piece of aluminum, a piece of copper and a piece of iron, and we measured their masses by using the balance. Also, we measured their volume by using a cylinder with distilled water, then we have measured the volume, and then we put in the metal and recorded the total volumes. After that we calculated each density and we recorded the average density (by classmates)....

...purpose of the lab was to determine density of both regular and irregular shaped objects. Throughout the lab I found out that both of the small and large silver rod, do not have the same density, and also found out that the gold rod is not real gold.
My hypothesis is that since, the large and small silver rod has about the same density I believe that they would have about the same amount of volume. They both might displace the same amount of water on the graduated cylinder.
The Materials we used throughout the lab was:
Metal rods (Gold & Silver)
Wooden block
Water
Scale
Ruler
Graduated cylinder
Procedure thought out the lab:
1. First step we did was get the materials and went to out stations with our partners.
2. Second me and my partner measured the mass of the metal rods and the wooden block and recorded them on the worksheet.
3. After we filled up the graduated cylinder with water and dropped one of the metal rods and the water, the water amount that increased in the cylinder was the volume of the rode that was placed in.
4. We continued to measure and record the volume of each of the metal rods the same way as the first.
5. We measured the length, width, and height of the wooden block and recorded it. Then multiplied them altogether to get the volume of the block.
6. After gaining the measurements of the mass and volume of the metal rods and the wooden block, me and my partner then used both the mass and volume to...

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