Q: A sample of bismuth contains $$ 5.40 \times 10$$^{14}$$ $$ atoms. What is the mass of this sample in micrograms ($$ \mu g $$)? (Atomic mass of Bi = 208.98 amu, $$ 1 \text{ mol} = 6.022 \times 10$$^{23}$$ $$ atoms)

$$ 1.87 \times 10$$^{-5}$$ \ \mu g $$

Q: The energy of a photon is given by $$ E_p = h \nu . If $$the frequency of a photon is $$ 6.0 \times 10$$^{14}$$ Hz$$, what is its energy in joules? ($$ h = 6.626 \times 10$$^{-34}$$ J$$·s)

$$ 3.98 \times 10$$^{-19}$$ J$$

Question 1

Which of the following best illustrates the Law of Definite Proportions?

Accepted Answer

Two samples of carbon dioxide, regardless of their source, always contain carbon and oxygen in a mass ratio of 12:32.

Question 2

A scientist observes that when magnesium metal is burned in air, it forms a white powder and releases energy as heat and light. Which of the following best describes this observation?

Accepted Answer

Observation

Question 3

Which experiment provided evidence for the existence of the electron as a subatomic particle?

Accepted Answer

Thomson cathode ray tube experiment

Question 4

A neutral atom of iron-56 ($$ ^{56}\mathrm{Fe} ) $$has how many protons, neutrons, and electrons?

Accepted Answer

26 protons, 30 neutrons, 26 electrons

Question 5

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 6

Which of the following correctly gives the symbol for the ion with 26 electrons and 32 neutrons?

Accepted Answer

$$ ^{58}\mathrm{Fe}^{2+} $$

Question 7

A sample of bismuth contains $$ 5.40 	imes 10$$^{14}$$ $$ atoms. What is the mass of this sample in micrograms ($$ \mu g $$)? (Atomic mass of Bi = 208.98 amu, $$ 1 	ext{ mol} = 6.022 	imes 10$$^{23}$$ $$ atoms)

Accepted Answer

$$ 1.87 	imes 10$$^{-5}$$ \ \mu g $$

Question 8

Which of the following statements about electromagnetic radiation is true?

Accepted Answer

As the energy of light increases, the frequency increases and the wavelength decreases.

Question 9

The energy of a photon is given by $$ E_p = h 
u . If $$the frequency of a photon is $$ 6.0 	imes 10$$^{14}$$  Hz$$, what is its energy in joules? ($$ h = 6.626 	imes 10$$^{-34}$$  J$$·s)

Accepted Answer

$$ 3.98 	imes 10$$^{-19}$$  J$$

Question 10

Which of the following quantum number sets is NOT valid for an electron in an atom?

Accepted Answer

$$ n = 2, \ l = 2, \ m_l = 0, \ m_s = +\frac{1}{2} $$

Question 11

Which of the following best describes Hund's Rule?

Accepted Answer

Electrons fill degenerate orbitals singly with parallel spins before pairing up.

Question 12

Which of the following ions is INCORRECTLY matched with its charge?

Accepted Answer

Br: 1+

Question 13

A cheetah can sprint 100.0 yards in 2.73 seconds. What is its speed in km/hr? (1 yard = 0.9144 m, 1 km = 1000 m)

Accepted Answer

$$ 121  km/hr$$

Question 14

Which of the following is an example of an intensive property?

Accepted Answer

Density

Question 15

Which of the following statements about the Bohr model of the atom is correct?

Accepted Answer

Electrons can only have certain values of energy within the atom.

Question 16

Which of the following best describes the result of Rutherford's gold foil experiment?

Accepted Answer

Atoms are mostly empty space with a small, dense, positively charged nucleus.

Question 17

A student measures the length of an object as 15.00 cm using a ruler marked in millimeters. How many significant figures should be reported?

Accepted Answer

4

Question 18

Which of the following best describes the Law of Conservation of Mass?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 19

Which of the following is a correct relationship for metric prefixes?

Accepted Answer

$$ 1 \ \mathrm{Gm} = 10^9$ \ \mathrm{m} $$

Question 20

Which of the following best describes the Heisenberg uncertainty principle?

Accepted Answer

The more accurately you know the position of an electron, the less accurately you can know its velocity.

General Chemistry Fundamentals: Atomic Structure, Measurement, and Chemical Laws

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