INAYA Medical Science College
GENERAL CHEMISTRY LABORATORY
Practical # 1
Density
Name:
ID Number:
Section
Date:
Mark:
T: Rashida .M.Hussein
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Our Goal:
Calculate the density of a substance from measurements of its mass
and volume.
Discussion
A. Density of a solid:
To determine the density of a substance, you need to measure
both its mass and its volume. From the mass and volume the
density is calculated. If the mass is measured in grams and the
volume in milliliters, the density will have the units of g / mL.
Density of a substance = Mass (g) of substance
Volume (mL) of substance
B. Density of a Liquid:
To determine the density of a liquid, you need the mass and
volume of the liquid. The mass of a liquid is determined by
weighting. The mass of a container is obtained and then a
certain volume of liquid is added and the combined mass
determined. Subtracting the mass of the container gives the
mass of the liquid. From the mass and volume, the density is
calculated.
Density of a liquid = Mass (g) of liquid
Volume (mL) of liquid
Experimental Procedure:
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A. Density of a solid:
-Materials: Metal object, string or thread, graduated cylinder.
A.1- Mass of the solid obtains a solid metal object. Determine
it’s mass and record.
A.2- Volume of the solid by displacement obtain a graduated
cylinder that is large enough to hold the solid metal object.
Add water until the cylinder is about half full. Read the water
level carefully and record.
If the solid is heavy, lower it into the water by attaching a string
or thread. While the solid object is submerged in the water,
record the final water level.
Calculate the volume of the solid.
Volume of solid = Final water level – initial water level
A.3- Calculating the density of the solid Calculate the density
(g/ mL) of the solid
Density of solid =
Mass (g) of solid
Volume (mL) of solid
A.4- Use the density you calculated for the solid to identify the
metal from the known values for density.
Table : Density values for some metals:
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Substance
Aluminum
Copper
Iron
Lead
Nickel
Tin
Zinc
Density (g/mL)
2.70
8.89
7.86
11.4
8.85
7.18
7.19
B. Density of a Liquid
Materials: 50 mL graduated cylinder, two liquid samples,
100mL or 250mL beaker.
B.1- Volume of liquid place about 20 mL of water in a 50 mL
graduated cylinder. Record
(Do not use the markings on beakers to measure volume;
they are not precise)
B.2- Mass of liquid The mass of liquid is found by weighing by
difference.
First, determine the mass of a small, dry beaker.
Pour the liquid into the beaker, and reweight.
Record the combined mass. Be sure to write down all the
figures in the measurements.
Calculate the mass of the liquid.
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Note:
Taring a container on an electronic balance: the mass of a
container on an electronic balance can be set to 0 by pressing
the tare bar.
As a substance is added to the container, the mass shown on the
readout is for the substance only. (When a container is tared, it
is not necessary to subtract the mass of the beaker.)
B.3- Density of liquid Calculate the density of the liquid by
dividing its mass (g) by the volume (mL) of the liquid.
Density of liquid = Mass (g) of liquid
Volume (mL) of liquid
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Report sheet
Density
A. Density of Solid
A.1 Mass of the solid
---------------------------------------------------
A.2 Volume of the solid by displacement
Initial water level (mL) ---------------------------------------------------Final water level with solid (mL) ---------------------------------------Volume of solid (mL) ----------------------------------------------------A.3 Calculating the density of the solid ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------A.4 Type of metal ---------------------------------------------------------
**************
B. Density of a liquid
B.1 Volume of liquid
Type of liquid --------------------------------------------------------------Volume (mL) ---------------------------------------------------------------
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B.2 Mass of liquid
Mass of beaker ------------------------------------------------------------Mass of beaker + liquid --------------------------------------------------Mass of liquid -------------------------------------------------------------B.3 Density of liquid
Density
(Show the calculations of density)
-----------------------------------------------------------------------------------------------------------------------------------------
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