1. Intro to General Chemistry

Density of Geometric Objects

MEASURING THE DENSITY OF A REGULAR SOLID - science experiments to try yourself

What is the edge length (in cm) of a titanium cube that contains
2.55 * 1024 titanium atoms? The density of titanium is
4.50 g/cm3.

What is the density of lithium metal in g/cm3 if a cylindrical wire with a diameter of 2.40 mm and a length of 15.0 cm has a mass of 0.3624 g?

(b) Using the mass of the proton
from Table 2.1 and assuming its diameter is 1.0 * 10-15 m,
calculate the density of a proton in g>cm3.

A steel cylinder has a length of 2.16 in, a radius of 0.22 in, and a
mass of 41 g. What is the density of the steel in g>cm3?

A copper wire (density = 8.96 g/cm3) has a diameter of 0.32 mm. If a sample of this copper wire has a mass of 21.7 g, how long is the wire?

Neutron stars are composed of solid nuclear matter, primarily
neutrons. Assume the radius of a neutron is approximately
1.0 * 10 - 13 cm. Calculate the density of a neutron. [Hint: For a
sphere V = (4>3)pr3.] Assuming that a neutron star has the
same density as a neutron, calculate the mass (in kg) of a small
piece of a neutron star the size of a spherical pebble with a radius
of 0.10 mm.

Brass is a copper–zinc alloy. What is the mass in grams of a brass cylinder having a length of 1.62 in. and a diameter of 0.514 in. if the composition of the brass is 67.0% copper and 33.0% zinc by mass? The density of copper is 8.92 g/cm3, and the density of zinc is 7.14 g/cm3. Assume that the den-sity of the brass varies linearly with composition.

(a) Three spheres of equal size are composed of aluminum
1density = 2.70 g/cm32, s i lver 1density = 10.49 g/cm32,
and nickel 1density = 8.90 g/cm32. List the spheres from
lightest to heaviest.

U.S. 1-cent coin (a penny) has a diameter of 19 mm and a
thickness of 1.5 mm. Assume the coin is made of pure copper,
whose density and approximate market price are 8.9 g/cm3
and $2.40 per pound, respectively. Calculate the value of
the copper in the coin, assuming its thickness is uniform.

Carbon-12 contains six protons and six neutrons. The radius of
the nucleus is approximately 2.7 fm (femtometers) and the radius
of the atom is approximately 70 pm (picometers). Calculate
the volume of the nucleus and the volume of the atom.

 Correct, since the volume of A is smaller, the density will be larger. 

 For equal masses, the smaller the volume, the larger the density. 

 To have the same density, the volumes would have to be the same. 

 Since the masses are the same, the density will vary inversely with the volume. 

 Density is an intensive property and is the ratio of mass to volume. 

The two objects shown below have the same mass. Which has the largest density?<img src="https://media.pearsoncmg.com/ph/esm/esm_tro_chemistry_6/msa/content/practice-quiz/img/troama5_pq_c1q12.jpg" ALT="Two rectangles, labeled A and B. Rectangle B is more than twice the size (area) of Rectangle A." class="block">

The proton has a radius of approximately 1.0 * 10 - 13 cm and a
mass of 1.7 * 10 - 24 g. Determine the density of a proton for a
sphere V = (4>3) pr 3.

(c) A spherical ball of lead has a diameter of 5.0 cm. What is
the mass of the sphere if lead has a density of 11.34 g>cm3?
(The volume of a sphere is 14>32pr3, where r is the radius.)

Very small semiconductor crystals, composed of approximately
1000 to 10,000 atoms, are called quantum dots.
Quantum dots made of the semiconductor CdSe are now
being used in electronic reader and tablet displays because
they emit light efficiently and in multiple colors, depending
on dot size. The density of CdSe is 5.82 g/cm3.
(a) What is the mass of one 2.5-nm CdSe quantum dot?

Hydrogen cyanide, HCN, is a poisonous gas. The lethal dose is 
approximately 300 mg HCN per kilogram of air when inhaled. 
(a) Calculate the amount of HCN that gives the lethal dose 
in a small laboratory room measuring 3.5 * 4.5 * 2.5 m. 
The density of air at 26 C is 0.00118 g>cm3.

An 8.894 g block of aluminum was pressed into a thin 
square of foil with 36.5 cm edge lengths. 
(a) If the density of Al is 2.699 g>cm3, how thick is the foil 
in centimeters?

A copper refinery produces a copper ingot weighing 70 kg.
If the copper is drawn into wire whose diameter is 7.50 mm,
how many meters of copper can be obtained from the ingot?
The density of copper is 8.94 g>cm3. (Assume that the wire is
a cylinder whose volume V = pr2h, where r is its radius and h
is its height or length.)

Carbon-12 contains six protons and six neutrons. The radius of
the nucleus is approximately 2.7 fm (femtometers) and the radius
of the atom is approximately 70 pm (picometers). What percentage of the carbon atom’s volume is occupied by
the nucleus? (Assume two significant figures.)

How many 1-cm squares would it take to construct a square that
is 1 m on each side?

The single proton that forms the nucleus of the hydrogen atom
has a radius of approximately 1.0 * 10 - 13 cm. The hydrogen
atom itself has a radius of approximately 52.9 pm. What fraction of the space within the atom is occupied by the nucleus?

If the density of a certain spherical atomic nucleus is 1.0 x 1014 g/cm3 and its mass is 3.5 x 10-23 g, what is the radius in angstroms? (Å= 10−10 m)

Density of Regular and Irregular Objects

Density of Geometric Objects Example

Very small semiconductor crystals, composed of approximately 
1000 to 10,000 atoms, are called quantum dots. 
Quantum dots made of the semiconductor CdSe are now 
being used in electronic reader and tablet displays because 
they emit light efficiently and in multiple colors, depending 
on dot size. The density of CdSe is 5.82 g/cm3. 
(c) What is the mass of one 6.5-nm CdSe quantum dot?

What is the density of lead in g/cm3 if a rectangular bar mea-suring 0.50 cm in height, 1.55 cm in width, and 25.00 cm in length has a mass of 220.9 g?

Mercury is often used in thermometers. The mercury sits in a
bulb on the bottom of the thermometer and rises up a thin
capillary as the temperature rises. Suppose a mercury thermometer contains 3.380 g of mercury and has a capillary that
is 0.200 mm in diameter. How far does the mercury rise in the
capillary when the temperature changes from 0.0 °C to 25.0 °C?
The density of mercury at these temperatures is 13.596 g>cm3
and 13.534 g>cm3, respectively

(d) A cubic piece of metal 
measures 5.00 cm on each edge. If the metal is nickel, whose 
density is 8.90 g>cm3, what is the mass of the cube?

Find the density of a solid

Imagine that you place a cork measuring 1.30 cm * 5.50 cm * 3.00 cm in water and that on top of the cork you place a small cube of lead measuring 1.15 cm on each edge. The density of cork is 0.235 g/cm3, and the density of lead is 11.35 g/cm3. Will the combination of cork plus lead float or sink?

Lead metal can be extracted from a mineral called galena, which
contains 86.6% lead by mass. A particular ore contains 68.5%
galena by mass. If the lead can be extracted with 92.5% efficiency, what mass of ore is required to make a lead sphere with a
5.00-cm radius?

Density of Regular Objects

A thief uses a can of sand to replace a solid gold cylinder that sits
on a weight-sensitive, alarmed pedestal. The can of sand and the
gold cylinder have exactly the same dimensions (length = 22
and radius = 3.8 cm).
a. Calculate the mass of each cylinder (ignore the mass of the
can itself). (density of gold = 19.3 g>cm3, density of sand
= 3.00 g>cm3)
b. Does the thief set off the alarm? Explain.

Calculate the volume in liters of a rectangular object with 
dimensions 13.0 cm * 11.0 cm * 12.0 cm. 
(a) 1720 L (b) 1.72 L 
(c) 14.3 L (d) 2.41 L

How to Calculate Density of a Solid Object | Real Example

Rolls of aluminum foil are 304 mm wide and 0.016 mm thick.
What maximum length of aluminum foil can be made from
1.10 kg of aluminum?

(c) Using the 
volume of a silver atom and the formula for the volume of a 
sphere, calculate the radius in angstroms of a silver atom.

The density of silver is 10.5 g/cm3. What is the mass (in kilo-grams) of a cube of silver that measures 0.62 m on each side?

Common Core Math: Volume and Density of 3D Geometric Shapes

A solid aluminum sphere has a mass of 85 g. Use the density of
aluminum to find the radius of the sphere in inches.

Lignum vitae is a hard, durable, and extremely dense wood used to make ship bearings. A sphere of this wood with a diameter of 7.60 cm has a mass of 313 g. 
(a) What is the density of the lignum vitae sphere? 
(b) Will the sphere float or sink in water? 
(c) Will the sphere float or sink in chloroform? (The density of chloroform is 1.48 g/mL.)

How to find the density of a solid

Density of Geometric Objects Concept

Density of Regular and Irregular Solids - IGCSE Physics

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2. Atoms & Elements

3. Chemical Reactions

4. BONUS: Lab Techniques and Procedures

5. BONUS: Mathematical Operations and Functions

6. Chemical Quantities & Aqueous Reactions

7. Gases

8. Thermochemistry

9. Quantum Mechanics

10. Periodic Properties of the Elements

11. Bonding & Molecular Structure

12. Molecular Shapes & Valence Bond Theory

13. Liquids, Solids & Intermolecular Forces

14. Solutions

15. Chemical Kinetics

16. Chemical Equilibrium

17. Acid and Base Equilibrium

18. Aqueous Equilibrium

19. Chemical Thermodynamics

20. Electrochemistry

21. Nuclear Chemistry

22. Organic Chemistry

23. Chemistry of the Nonmetals

24. Transition Metals and Coordination Compounds

[BOOK CHEM] Clutch Version

SI Units

The International System of Units (SI) is related to the metric system and is based on seven base units.

Physical & Chemical Changes

A physical change involves a change in the phases of matter, whereas a chemical change involves a change in chemical bonds.&nbsp;

Physical Properties

Physical Properties are measurable properties that describe the state of chemical compounds.&nbsp;

Significant Figures: In Calculations

Significant Figures are often involved in chemical calculations.&nbsp;

Scientific Notation

Scientific Notation is used to turn small or large inconvenient numbers into manageable ones.&nbsp;

Density of Non-Geometric Objects

The density of non-geometric objects can be determined using water displacement.&nbsp;

Density

Density represents the mass of an object or compound within a given volume.&nbsp;

Significant Figures: Precision in Measurements

Significant Figures are used to discuss the level of precision in any measurement.&nbsp;

Intensive vs. Extensive Properties

Intensive Properties are independent and Extensive Properties are dependent on the size or amount of substance present

The density of geometric objects generally includes spheres, cubes and cylinders.&nbsp;

Significant Figures

Significant Figures are used to determine some level of accuracy within our recorded measurements.&nbsp;

Dimensional Analysis

We use dimensional analysis&nbsp;as a fail proof process to convert from one unit to another.

Chemical Properties

Chemical Properties are observed during chemical reactions.&nbsp;

Temperature

Temperature is a measure of the amount of average kinetic energy of the atoms in a compound.

Metric Prefixes

Metric Prefixes are “labels” that can be placed in front of base units.&nbsp;

Conversion Factors

Conversion Factors represent ratios or fractions composed of different units.&nbsp;

Classification of Matter

Chemistry is the study of matter and the changes it undergoes, with the atom being its basic functional unit.&nbsp;