Q: A student wants to determine the density of an irregularly shaped rock. She places the rock in a graduated cylinder containing 50.0 mL of water, and the water level rises to 65.5 mL. If the mass of the rock is 42.0 g, what is its density?

$$\text{Density} = \frac{42.0\ \text{g}}{15.5\ \text{mL}} = 2.71\ \text{g/mL}$$

Q: A patient receives a dose of medication measured as $$2.5\ \text{mg}. If $$the pharmacist needs to convert this to micrograms $$(\mu\text{g})$$, what is the correct value?

$$2.5\ \text{mg} \times \frac{1000\ \mu\text{g}}{1\ \text{mg}} = 2500\ \mu\text{g}$$

Q: A wave has a frequency of $$6.0 \times 10$$^{14}$$\ \text{Hz}$$ and a wavelength of $$5.0 \times 10$$^{-7}$$\ \text{m}. $$What is the speed of the wave?

$$c = \lambda \nu = (5.0 \times 10$$^{-7}$$\ \text{m})(6.0 \times 10$$^{14}$$\ \text{Hz}) = 3.0 \times 10$$^{8}$$\ \text{m/s}$$

Question 1

A student wants to determine the density of an irregularly shaped rock. She places the rock in a graduated cylinder containing 50.0 mL of water, and the water level rises to 65.5 mL. If the mass of the rock is 42.0 g, what is its density?

Accepted Answer

$$	ext{Density} = \frac{42.0\ 	ext{g}}{15.5\ 	ext{mL}} = 2.71\ 	ext{g/mL}$$

Question 2

Which of the following best describes the main purpose of using significant figures in scientific measurements?

Accepted Answer

To ensure measurements reflect the precision of the measuring instrument.

Question 3

A patient receives a dose of medication measured as $$2.5\ 	ext{mg}. If $$the pharmacist needs to convert this to micrograms $$(\mu	ext{g})$$, what is the correct value?

Accepted Answer

$$2.5\ 	ext{mg} 	imes \frac{1000\ \mu	ext{g}}{1\ 	ext{mg}} = 2500\ \mu	ext{g}$$

Question 4

Which of the following statements about ions is correct?

Accepted Answer

An ion is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

Question 5

Which of the following best defines isotopes of the same element?

Accepted Answer

Atoms with the same number of protons but different numbers of neutrons.

Question 6

A neutral atom of sodium ($$^{23}_{11}	ext{Na}) $$loses one electron. What is the resulting ion's charge and symbol?

Accepted Answer

$$	ext{Na}^+$$

Question 7

Which subatomic particle is neutral and found in the nucleus of an atom?

Accepted Answer

Neutron

Question 8

Which of the following statements about the periodic table is correct?

Accepted Answer

A period is a horizontal row of elements.

Question 9

Which of the following best defines transition metals?

Accepted Answer

Elements found in groups 3 to 12 of the periodic table.

Question 10

What is the primary difference between atomic mass and atomic number?

Accepted Answer

Atomic mass is the average mass of all isotopes, while atomic number is the number of protons.

Question 11

According to the Pauli exclusion principle, which of the following is true about electrons in the same orbital?

Accepted Answer

No two electrons in an orbital can have the same spin.

Question 12

A wave has a frequency of $$6.0 	imes 10$$^{14}$$\ 	ext{Hz}$$ and a wavelength of $$5.0 	imes 10$$^{-7}$$\ 	ext{m}. $$What is the speed of the wave?

Accepted Answer

$$c = \lambda 
u = (5.0 	imes 10$$^{-7}$$\ 	ext{m})(6.0 	imes 10$$^{14}$$\ 	ext{Hz}) = 3.0 	imes 10$$^{8}$$\ 	ext{m/s}$$

Question 13

Which of the following best describes an electron shell in atomic structure?

Accepted Answer

A region around the nucleus where electrons are likely to be found.

Question 14

Which of the following statements about electron affinity is correct?

Accepted Answer

Electron affinity is the energy released when an electron is added to a gaseous atom.

Question 15

Which of the following is a correct designation for a subshell?

Accepted Answer

2p

Question 16

A scientist observes a series of colored lines when hydrogen gas is excited and the emitted light is passed through a prism. What is this phenomenon called?

Accepted Answer

Emission spectrum

Question 17

Which of the following is the primary feature of the Bohr model of the atom?

Accepted Answer

Electrons travel in circular orbits around the nucleus.

Question 18

Which of the following best describes the electromagnetic spectrum?

Accepted Answer

A continuum of electromagnetic radiation encompassing all wavelengths and frequencies.

Question 19

Which metric prefix corresponds to $$10^9$$?

Accepted Answer

Giga

Question 20

A chemist writes the condensed electron configuration for chlorine as $$[	ext{Ne}]3s^2$ 3p^5$. What is the main advantage of using this notation?

Accepted Answer

It provides a faster way to write electron arrangements for elements or ions.

Step-by-Step Guidance for Introduction to Chemistry Exam Prep (Ch 1, 2, 4, 9)

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