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2.5 The Structure of the Atom -- Part 4
This example shows how to use conversion factors.
To solve the problem, follow the conceptual plan.
The amount in moles is less than 1mol of carbon, so it makes sense that the answer is less than that.
We now have the ability to count the number of atoms in a sample by weighing it.
The mass of the sample is obtained first.
We use the element's mass to convert it to moles.
Avogadro's number is used to convert it to number of atoms.
3.10 g Cu was asked to find the number of copper atoms.
Cu factors arrive at the number of Cu atoms.
The number of copper atoms is less than 1023.
The given mass of copper atoms is less than the molar mass.
Diamonds are made from pure carbon.
6.022 * 1023 are almost unbelievably large.
To cover Earth's entire surface to a depth of 300 m, twenty-two copper pennies contain 6.022 * 1023 or 1 mol of copper atoms.
When we have a mole of an object, it occupies a huge space.
One mol of sand would cover the state of Texas to a depth of several feet, even though the grain has a mass of less than 1mg and a diameter of less than 0.1mm.
1023 is incredibly large because the number increases by a factor of 10 when the number is increased.
If 1mol is to have practical value, it has to be a large number.
An aluminum sphere has 1022 aluminum atoms.
2.70 g> cm3 is the density of aluminum.
You are asked to find the center of the sphere.
Use density as a conversion factor to convert from mass to volume.
Follow the conceptual plan to solve the problem.
1022 Al atoms and 6.022 Al atoms are equal to 26.98 g Al 1 cm3 and arrive at volume in cm3.
The units of the answer are correct.
The magnitude can't be estimated accurately, but it is reasonable to think of just over one-tenth of a mole of aluminum atoms.
A titanium cube has 1023 atoms.
The density of titanium is very low.
The density of copper is close to 9 g.
Determine which sample has the most atoms.
What is the charge for the electron?
A and B are produced in the first sample.
The a carbon-to-hydrogen mass ratio is 11.89.
An element has a number of protons and a number of neutrons.
Determine the number of electrons in the ion.
A naturally occurring sample of an element.
The natural abundance of the first isotope is 60.11%.
There is a mass of 70.9247 amu.
Determine the number of atoms in mercury.
A 20.0 g sample of an element has 1023 atoms.
The element should be identified.
The motion of small particles is known as Brownian motion and is caused by three fundamental particles.
Each element is composed of particles that have different numbers of neutrons.
All atoms of an element have the same mass and other atoms that lose or gain electrons become charged and are ionized.
There are two types of charges: positively charged and negatively charged.
There are simple whole-number ratios to form com pounds.
The periodic table tabulates all known elements in order of ment.
In a chemical reaction, atoms change their behavior.
Similar elements are grouped together in columns in the periodic table.
The periodic table has elements on the left side and on the center.
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