Question 1

Which of the following is an example of a physical change?

Accepted Answer

Dissolving table salt (NaCl) in water

Question 2

A sample of copper is heated from $$25\ ^\circ\mathrm{C} to$$ $$75\ ^\circ\mathrm{C}$$, absorbing $$835\ \mathrm{J} of $$heat. If the mass of copper is $$50.0\ \mathrm{g}$$, what is the specific heat capacity of copper? (Use $$q = m c \Delta T)$$

Accepted Answer

$$0.167\ \mathrm{J/g\ ^\circ C}$$

Question 3

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout

Question 4

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 5

Which element is a metalloid and is commonly used in computer chips due to its semiconducting properties?

Accepted Answer

Silicon ($$\mathrm{Si})$$

Question 6

Which of the following best describes the process of sublimation?

Accepted Answer

A solid changing directly to a gas without passing through the liquid state

Question 7

A neutral atom of phosphorus ($$\mathrm{P}) $$has an atomic number of 15 and a mass number of 31. How many neutrons does it have?

Accepted Answer

16

Question 8

Which of the following electron configurations represents a magnesium ($$\mathrm{Mg}) $$atom?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$

Question 9

Which of the following statements about metals is true?

Accepted Answer

Metals are good conductors of heat and electricity

Question 10

Which of the following changes is a chemical change?

Accepted Answer

Burning wood

Question 11

Which of the following best describes the atomic theory as proposed by John Dalton?

Accepted Answer

All matter is composed of small, indivisible particles called atoms

Question 12

Which of the following elements is a noble gas?

Accepted Answer

Helium ($$\mathrm{He})$$

Question 13

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

Accepted Answer

Elements in the same group have similar chemical properties

Question 14

A sample contains 80% $$^{35}\mathrm{Cl} ($$atomic mass = 34.97 u) and 20% $$^{37}\mathrm{Cl} ($$atomic mass = 36.97 u). What is the average atomic mass of chlorine in this sample?

Accepted Answer

$$35.37\ \mathrm{u}$$

Question 15

Which of the following best explains why sodium ($$\mathrm{Na}) is $$more reactive than magnesium ($$\mathrm{Mg}$$)?

Accepted Answer

Sodium has a lower ionization energy than magnesium

Question 16

Which of the following statements about subatomic particles is correct?

Accepted Answer

Protons and neutrons are found in the nucleus, while electrons are found outside the nucleus

Question 17

Which of the following best describes the trend in metallic character across a period from left to right on the periodic table?

Accepted Answer

Metallic character decreases

Question 18

Which of the following is the correct order of increasing energy for the following types of electromagnetic radiation: visible light, ultraviolet, infrared?

Accepted Answer

Infrared \u003c Visible light \u003c Ultraviolet

Question 19

Which of the following best describes the arrangement of electrons in an atom according to the modern atomic model?

Accepted Answer

Electrons occupy specific energy levels and are found in orbitals within subshells

Question 20

A patient is treated for a thyroid disorder using radioactive iodine-131. Which property of isotopes makes this possible?

Accepted Answer

Isotopes of the same element have identical chemical properties but different nuclear properties

GOB Chemistry Study Guide: Matter, Elements, and Atomic Structure

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