Introduction:
The purpose of this lab will be to investigate the concepts of accuracy and precision for quantitative measurements using density as an example. The density of a sample will be found experimentally and compared to a known value. The relationship of averages and different analysis techniques to percent error will also be explored. Density is a characteristic of a substance which can qualitatively be described as the amount of matter (mass) squeezed into a given space (volume). The density of substance remains the same no matter the size of the sample at a given temperature. Quantitatively, density can be expressed as the mass of a substance per unit volume, and the volume of a cylinder can be expressed as π times the radius squared times the height. (Density=Mass/VolumeV = π(Diameter/2)^2 x Height)*

*Microsoft Word Starter 2010 does not allow creation of equations. This was the best alternative Materials:
Density sample cylinders; metric ruler; Electronic balance
Procedure:
Measure the mass, height, and diameter of five different cylinders from the substance as precisely as possible to ensure the correct measurements are recorded. Data Table:
Cylinder #| Mass (grams)| Height (centimeters)| Diameter (centimeters)| 2| 12.82g| 4.60cm| 1.55cm|
4| 16.51g| 5.60cm| 1.10cm|
8| 21.37g| 7.60cm| 1.60cm|
10| 24.09g| 8.60cm| 1.10cm|
14| 29.80g| 10.70cm| 1.10cm|

Analysis:
Graph -
Mass and Volume of Blue Cylindrical Objects
Mass and Volume of Blue Cylindrical Objects

Mass (g)
Mass (g)
Volume (cm^2)
Volume (cm^2)
`

Average Density Data Table -
Average Density (g/cm^3)| Team Average Density (g/cm^3)|
2.495 g/cm^3| 1.647 g/cm^3|

...
DENISTY LAB
2/25/13
Chemistry H.
Mrs. Halme
Objective: Your task is to determine the density of 3 known metals: Zinc, Copper, and Lead. They are each marked. You must then calculate the density of an unknown metal and determine its identity based on your data from your known samples.
Reagents: None
Equipment:
Lead
Copper
Zinc
Triple Beam Balance
Graduated cylinder
Unknown metal (Magnesium)
Beaker
Calculator
Procedures
Preparation:
We observed the given equipment, and then placed 100 Ml of water into a graduated cylinder.
Zinc
1. We then placed a sample of Zinc in the graduated cylinder.
2. The water level rose 4 ml. We subtracted the original 100mLof water from the 104mL of water with zinc in it. This gave us the volume of the zinc, being 4mL.
3. We then took the sample of Zinc and placed it on the Triple beam Balance.
4. We recorded the mass of the sample at 36.5 g.
5. We then recorded our results.
6. Then we divided the mass of the Zinc by the volume. This giving us the density of the sample being 9.125 mL/g.
7. We found the %error to be 27.8%, by subtracting our result minus the accepted value of the sample, multiplied by 100% divided by the accepted value.
Copper
1. We then placed a sample of Copper in the graduated cylinder.
2. The water level rose 3mL. We subtracted the original 100mL of water from the 103mL of water with Copper in it. This...

...
The Density Challenge: A Complete Inquiry Activity
Introduction
Density has been an important part of science for a very long time. Density was discovered by Archimedes, a Greek mathematician, around 250 BC while determining whether a craftsman had replaced some of the gold in the King of Syracuse’s crown with silver. Density is the compactness of a substance. The new concept ofdensity he discovered was used to expose the fraud. The purpose of this experiment is to make the heaviest floating film container without having it sink. The density of water is 1, so in order to keep the film container from sinking, the density of the sand-filled film container must be less than 1. The equation for density is D=m/V, where m is mass and v is volume. To find the volume of the film container, use the equation V=3.14r^2h, where r is the radius and h is the height. My hypothesis is that if the density of the sand-filled film container is less than the density of water, then the film container filled with sand will float. But, if the sand-filed container does not have less density than the water, then the container will sink. The independent variable is the amount of sand in the film container. The dependent variables are the mass and if the film container floats or sinks. The control...

...Regents Chemistry
Quarter 1 Midterm Review
1. The percent by mass of oxygen in Na2SO4
(formula mass = 142) is closest to
1) 11%
3) 45%
2) 22%
4) 64%
2. Given the unbalanced equation:
__Al(s) + __O2(g) → __Al2O3(s)
3.
4.
5.
6.
7.
balance the equation using smallest whole
number coefficients.
The percent by mass of aluminum in Al2O3 is
approximately
1) 18.9
3) 47.1
2) 35.4
4) 52.9
What is the approximate percent composition by
mass of CaBr2 (formula mass = 200)?
1) 20% calcium and 80% bromine
2) 25% calcium and 75% bromine
3) 30% calcium and 70% bromine
4) 35% calcium and 65% bromine
What is the empirical formula for C3H6?
1) CH
2) CH2
3) CH3
4) CH6
Which represents both an empirical and a
molecular formula?
1) P2O5
2) N2O4
3) C3H6
4) C6H12O6
The number of atoms in 2 grams of calcium is
equal to
1) 2 × 6.02 × 1023
40
2) 40 × 6.02 × 1023
2
3) 6.02 × 1023
2 × 40
4) 2 × 40 × 6.02 × 1023
8. At STP, 32 grams of O2 would occupy the same
volume as
1) 64 g of H2
2) 32 g of SO2
3) 8.0 g of CH4
4) 4.0 g of He
9. Which compound has the empirical formula CH2
O?
1) CH3OH
2) CH3CH2OH
3) HCOOH
4) CH3COOH
10. Which list consists of types of chemical
formulas?
1) atoms, ions, molecules
2) metals, nonmetals, metalloids
3) empirical, molecular, structural
4) synthesis, decomposition, neutralization
11. What is the total number of neon atoms
contained in 20.2 grams of neon gas?
3) 3.01 × 1023...

...!
Name: Laura Romero
!
5.04H: Gas Stoichiometry Lab Worksheet
Data and Observations:
Present all relevant data in a data table below. Include an observations section for any
observations that you made during the lab. (5 points)
Data Table
Mass of magnesium strip (grams)
0.032 g
Volume of gas collected (mL)
30mL
Barometric pressure (atm)
1.1 atm
Room Temperature (°C)
22 °C
Vapor pressure of the water (torr)
19.8 torr
!
!
Calculations:
!
1. Write the balanced equation for the reaction conducted in this lab, including
appropriate phase symbols. (2 points)
!
Mg(s) + 2HCl(a) + H2O(a) -> MgCl2(s) + H2 (g)
!
!
!
2. Determine the partial pressure of the hydrogen gas collected in the gas collection
tube. (3 points)
!
1.1 atm = 0.026 atm + h2
!
!
!
3. Calculate the moles of hydrogen gas collected. (4 points)
!
!
!
n = 1.074 atm x 0.03 L / 0.0821 x 295.15 K = 0.00133 mol H2
!
!
!
!
4. If magnesium was the limiting reactant in this lab, calculate the theoretical yield of the
gaseous product. Show all steps of your calculation. (4 points)
!
.032 g Mg * 1 mol Mg / 24.305 g Mg * 1mol h2 / 1 mol Mg = 0.0131
mol
!
!
!
!
!
5. Determine the percent yield of this reaction, showing all steps of your calculation. (3
points)
!
!
Percent Yield = 0.00133 /0.0131 mol H2 × 100 = 10. 15 %
!
!
!
!
!
!
Conclusion:
1. Would...

...Part I: Density of Unknown Liquid
Trial 1
Trial 2
Trial 3
Mass of Empty 10 mL graduated cylinder (grams)
25.55
25.56
25.55
Volume of liquid (milliliters)
8.8
8.65
8.5
Mass of graduated cylinder and liquid (grams)
30.65
30.62
30.565
Part II: Density of Irregular-Shaped Solid
Mass of solid
(grams)
39.537
38.515
40.975
Volume of water (milliliters)
50.01
49.9
52.4
Volume of water and solid (milliliters)
54.9
54
57
Part III: Density of Regular-Shaped Solid
Mass of solid (grams)
27.7
27.71
26.8
Length of solid (centimeters)
5.26
5
4.5
Width of solid (centimeters)
3
4
3.5
Height of solid (centimeters)
2.5
3
2
Part I: Density of Unknown Liquid
1. Calculate the mass of the liquid for each trial. (Subtract the mass of the empty graduated cylinder from the mass of the graduated cylinder with liquid.)
Trial 1 30.65-25.55=5.10
Trial 2 30.62-25.56=5.060
Trial 3 30.565-25.55=5.015
2. Calculate the density of the unknown liquid for each trial. (Divide the mass of the liquid calculated above by the volume of the liquid.)
Trial 1: 5.1/8.8=0.58
Trial 2: 5.06/8.65=.58
Trial 3: 5.015/8.5=0.59
Part II: Density of Irregular-Shaped Solid
3. Calculate the volume of the irregular-shaped solid for each trial. (Subtract the volume of the water from the total volume of the water and solid.)...

...Density of a regular shaped object
Object Mass / g
± 0.05 g * Length / cm
± 0.003 cm ** Width / cm
± 0.003 cm ** Height / cm
± 0.003 cm **
T1 T2 T3 T4 T5 T1 T2 T3 T4 T5 T1 T2 T3 T4 T5
A 44.9 5.975 5.980 5.980 5.980 5.975 1.500 1.500 1.500 1.500 1.500 0.600 0.600 0.605 0.600 0.600
B 16.5 4.400 4.395 4.400 4.395 4.395 1.500 1.500 1.495 1.500 1.495 0.300 0.305 0.305 0.300 0.300
C 22.5 3.000 2.995 3.000 3.000 3.000 1.500 1.505 1.495 1.500 1.500 0.600 0.595 0.600 0.595 0.595
D 22.6 6.005 6.000 6.010 6.005 6.000 1.500 1.500 1.495 1.500 1.495 0.295 0.300 0.300 0.305 0.300
E 11.4 3.040 3.045 3.040 3.075 3.070 1.500 1.495 1.500 1.500 1.495 0.300 0.300 0.305 0.300 0.300
F 5.80 1.550 1.550 1.540 1.550 1.550 1.495 1.500 1.500 1.495 1.500 0.300 0.300 0.300 0.300 0.300
Table 1: Raw data table
Half the smallest division: 0.1 ÷ 2 = 0.05 g
** Half the smallest division: 0.005 ÷ 2 = 0.0025 ≃ 0.003 cm
Inaccurate set of data due to random error. (See Evaluation)
Table 2: Data processing 1
Object Mass / g
± 0.05 g Average L / cm Abs. Unc. L / cm Average W / cm Abs. Unc. W / cm Average H / cm Abs. Unc. H / cm
A 44.9 5.98 0.006 1.50 0.003 0.60 0.007
B 16.5 4.40 0.006 1.50 0.006 0.30 0.006
C 22.5 3.00 0.007 1.50 0.008 0.60 0.006
D 22.6 6.00 0.009 1.50 0.006 0.30 0.008
E 11.4 3.06 0.03* 1.50 0.006 0.30 0.007
F 5.80 1.55 0.02* 1.50 0.006 0.30 0.003
Since the uncertainties can only be written with 1 s.f, the number of decimal places cannot...

...Jahzeel Morales
Jessa Arellano
September 19, 2014
Period 4
Lab #1: Density Determinations 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 solutions of...

...Ciara Clark and Caroline Bedenbaugh 4A
DensityLab
Objective
: The purpose of this lab is to observe and explore the relationship of a substance’s
volume vs. its mass, and to calculate an object's density by using the relationship of its mass
and volume.
Data Tables
:
Data: Density of Water
Run
Mass of graduated
cylinder
volume of water added
mass of water
1
25.28 g
0.00 mL
0.00 g
2
26.15 g
1.00 mL
0.87 g
3
27.18 g
2.00 mL
1.90 g
4
28.19 g
3.00 mL
2.91 g
5
29.13 g
4.00 mL
3.85 g
6
30.22 g
5.00 mL
4.94 g
Data: Density of a Solid 1
Run
Mass of Cylinder
Initial Volume of
Water
Final Volume of Volume of
Water
object
1
29.3 g
4.00 mL
4.00 mL
0.00 mL
2
33.0 g
4.00 mL
4.50 mL
0.50 mL
3
35.5 g
4.50 mL
4.80 mL
0.80 mL
4
39.4 g
4.80 mL
5.40 mL
1.40 mL
5
43.3 g
5.40 mL
5.60 mL
1.60 mL
1
Ciara Clark and Caroline Bedenbaugh 4A
Data: Density of a Solid 2
Run
Mass of
cylinder
initial volume
of water
Final volume of
water
Volume of
object
1
29.3 g
4.00 mL
4.00 mL
0.00 mL
2
33.0 g
4.00 mL
4.50 mL
0.50 mL
3
35.5 g
4.50 mL
4.80 mL
0.80 mL
4
39.4 g
4.80 mL
5.40 mL
1.40 mL
5
43.3 g
5.40 mL
5.60 mL
1.60 mL
Data Analysis
Data: Density of water
Run
Mass of water
Volume of water
1
0.00 g
0.00 mL
2
0.87 g
1.00 mL
3
1.90 g
2.00 mL
4
2.91 g
300 mL
5
3.85 g
4.00 mL
Data:...