Chemistry Chapter 1 & 2

It is possible to determine the ionization energy for hydrogen using the Bohr equation. Calculate the ionization energy for an atom of hydrogen, making the assumption that ionization is the transition from n = 1 to n = ∞.

2.18 x 10^-18 J

An FM radio station broadcasts electromagnetic radiation at a frequency of 101.2 MHz. The wavelength of this radiation is ________ m.

2.964

Naturally occurring magnesium has an atomic mass of 24.312 and consists of three isotopes. The major isotope is 24Mg, natural abundance 78.99 %, relative atomic mass 23.98504. The next most abundant isotope is 26Mg, relative atomic mass 25.98259. The third isotope is 25Mg whose natural abundance is in the ratio of 0.9083 to that of 26Mg. Find the relative atomic mass of 25Mg?

25.06 amu

What speed does light travel at?

3.00 x 10^8 m/s

How many atoms of oxygen are in 2.50 moles of SO2?

3.01 x 10^24 atoms

A new element was recently discovered and found to have an atomic weight of 342.38 amu. This element has two isotopes, the lighter of which has a mass of 340.91 amu and an abundance of 68.322%. What is the mass of the heavier isotope?

345.55

Electromagnetic radiation with a wavelength of 641 nm appears as orange light to the human eye. The energy of one photon of this light is 3.10 × 10^−19. Thus, a laser that emits 1.3×10^−21 J of energy in a pulse of light at this wavelength produces ________ photons in each pulse.

4.2 x 10^16

How many atoms are in 2.50 moles of SiO2?

4.52 x 10^24

violets wavelength?

400nm

Consider a hypothetical element X that consists of two isotopes, one with a mass of 41.99998 amu and the other with a mass of 44.99987 amu. Their percent abundances are 33.3333% and 66.6667%, respectively. Without doing an actual calculation, the mass closest to the atomic mass of X is ______.

44.0 amu

Compare the characteristics of 4d orbitals and 3d orbitals and complete the following sentences.

4d orbitals would have more nodes and be large in size than 3d orbitals

Which of the following set of quantum numbers (ordered nn ℓℓ, mℓmℓ) are possible for an electron in an atom?

5, 3, 0

What are the possible values of mℓmℓ for an electron in a d orbital?

-2, -1, 0, 1, 2

What is the only possible value of mℓmℓ for an electron in an s orbital?

0

How much energy (in JJ) is contained in 1.00 mole of 706 nm photons?

1.69 x 10^5 J

A hydrogen-filled balloon was ignited and 1.90 g of hydrogen reacted with 15.2 g of oxygen. How many grams of water vapor were formed?

1.90 + 15.2 = 17.1 g

how many neutrons are in magnesium-24?

12 `

1s orbitals

does not have any nodes

What does the principal quantum number determine?

energy and size of the orbital

law

generally describes a series of past observations and predicts future observations

2p orbitals

have a node at the nucleus

Scientific law

is a brief statement that summarizes past observations and makes predictions

What wavelength λλ should the astrophysicist look for to detect a transition of an electron from the n=6n=6 to the n=3n=3 level?

lamda= 1.09 x 10^-6m

Compound

molecule composed of two different types of atoms

Which of the following electron transitions corresponds to electromagnetic radiation with the largest frequency?

5f to 2p

Calculate the mass (in g) of 2.0 × 10^24 atoms of Hg.

6.5 x 10^2

How many orbitals are present when l=3?

7

what is red lights wavelength

750 nm; the longest visible light

How many orbitals are contained in the third principal level (n = 3) of a given atom?

9

Compare a 2px orbital and a 4pz orbital.

Both orbitals have the same basic shape, but they differ in orientation and number of nodes.

Which of the following contains the most atoms? a) 10.0 g Cs b) 10.0 Ca c) 10.0 He

C. 10.0 He

A sample of a compound containing only carbon oxygen decomposes and produces 24.50g of carbon and 32.59g of oxygen. What is this Sample?

CO

The existence of a nuclear structure in an atom was indicated by which of the following results of Rutherford's experiment?

Deflection of alpha particles at very large angles

A scientist shines light with energy greater than the binding energy of platinum on a thin film of it. The same scientist then repeats the experiment with a higher intensity light. According to the photoelectric effect, what should be observed?

Electrons are ejected in both experiments at the exact same time

Two iron oxide samples are given to you where one is red and the other is black. You perform a chemical analysis and you find that the red sample has a Fe/O mass ratio of 2.327 and the black has a Fe/O mass ratio of 3.491. You suspect the red sample is simple rust or Fe2O3. What is the chemical formula for the black sample?

FeO;

How many helium atoms are there in a helium blimp containing 542 kg of helium?

N = 8.15 x 10^28 atoms

True or false: As the energy from electromagnetic radiation decreases the frequency decreases

True

What is an example of a homogenous mixture

air

What are the charges on the Millikan's experiment oil drops?

all multiples of -1.60 x 10^-19C

What are the possible values of the magnetic quantum number ml?

all the integers in range from -l to +l, where l is an angular momentum quantum number

What are the possible values of the angular momentum quantum number l?

all the non-negative integers: 0,1,2,..., n-1, where n is a principal quantum number

What are the possible values of the principal quantum number n?

all the positive integers: 1,2,3, etc.

3d orbitals

clover leaf shape with 4 lobes of electron density around the nucleus and 2 perpendicular nodal planes

pure substance

composed if one type of particle

Observations

describe or measure a process or an event

What is the de Broglie wavelength of an electron traveling at 1.05×105m/s.

lamda= 6.93 nm

Which of the following quantum numbers describes the orientation of an orbital?

magnetic quantum number

How many gold atoms are in a 0.467 ounce, 18 KK gold bracelet? (18 KK gold is 75% gold by mass.)

n = 3.0x10^22

How many moles of aluminum do 4.30×10^24 aluminum atoms represent?

n = 7.14 mol

Which of the following transitions represent the emission of a photon with the largest energy?

n=3 to n=1

According to the Bohr model of the atom, which electron transition would correspond to the shortest wavelength line in the visible emission spectra for hydrogen?

n=6 to n=2

Theory

not only describes an action or observation in nature but also why the action my take place

frequency

number of cycles that pass through a stationary point in a given period of time; inversely proportional to the wavelength

What does the magnetic quantum number determine?

orientation of orbital

What does the angular momentum quantum number determine?

shape of orbital

Daltons Atomic theory states

that matter is composed of small indestructible particles

Wavelength

the distance in space between adjacent crests and is measured in units of distance; determines color of visible light

As the wavelength of electromagnetic radiation increases _______.

the frequency decreases and the energy per photon decreases

All statements about scientific theories are true except

they are speculations

What represents isotopes?

top number in ratio represents neutrons

True or false: some elements have 3 or more naturally occurring isotopes

true

True or false: the magnetic quantum number describes the orientation of the orbital?

true

A laser dazzles the audience in a rock concert by emitting green light with a wavelength of 523 nm. Calculate the frequency of the light.

v = 5.74 x 10^14 s^-1 the frequency is found by dividing the speed of light (in meters per second) by the wavelength (in meters)

amplitude

vertical height of the crest

What is an example of a hypothesis

when a substance combusts, it combines with air

de Broglie equation

λ = h/mv; baseball and an electron are alike that they can both be described by this equation