CHEMISTRY CHAPTER 2

Exercise 2.50: Problems by Topic - Atomic Theory, Nuclear Theory, and Subatomic Particles

Which of the following statements about subatomic particles are false?

Part A

Protons and electrons have charges of the same magnitude but opposite sign.

Part B

Protons have about the same mass as neutrons.

Part C

Some atoms don't have any protons.

Part D

Protons and neutrons have charges of the same magnitude but opposite sign.

Exercise 2.58: Problems by Topic - Isotopes and Ions

Uranium-235 is used in nuclear fission.

Part A

Determine the number of protons and neutrons in uranium-235.

Enter your answers numerically separated by a comma.

Part B

Write its symbol in the form AZX.

Express your answer as an isotope.

Exercise 2.60: Problems by Topic - Isotopes and Ions

Determine the number of protons and electrons in each of the following.

Part A

Zn2+

Enter your answers numerically separated by a comma.

Part B

P3−

Enter your answers numerically separated by a comma.

Part C

Fe3+

Enter your answers numerically separated by a comma.

Part D

Sr2+

Enter your answers numerically separated by a comma.

Exercise 2.74: Problems by Topic - The Periodic Table and Atomic Mass

Silicon has three naturally occurring isotopes with the following masses and natural abundances:

Part A

Calculate the atomic mass of silicon.

Exercise 2.79: Problems by Topic - The Mole Concept

Part A

How many sulfur atoms are there in 4.5 mol of sulfur?

Express your answer using two significant figures.

Exercise 2.81: Problems by Topic - The Mole Concept

What is the amount, in moles, of each of the following substances?

Part A

12.2 gAr

Part B

3.75 gZn

Part C

26.6 gTa

Part D

0.219 gLi

Exercise 2.82: Problems by Topic - The Mole Concept

What is the mass, in grams, of each of the following?

Part A

2.3×10⁻³ molSb

Express your answer using two significant figures.

Part B

3.53×10⁻² molBa

Express your answer using three significant figures.

Part C

43.6 molXe

Express your answer using three significant figures.

Part D

1.1 molW

Express your answer using two significant figures.

Exercise 2.76: Problems by Topic - The Periodic Table and Atomic Mass

The atomic mass of copper is 63.546 amu

Part A

Do any copper isotopes have a mass of 63.546 amu?

Part B

Explain.

Exercise 2.36: Problems by Topic - The Laws of Conservation of Mass, Definite Proportions, and Multiple Proportions

Upon decomposition, one sample of magnesium fluoride produced 1.65 kg of magnesium and 2.57 kg of fluorine. A second sample produced 1.31 kg of magnesium.

Part A

How much fluorine (in grams) did the second sample produce?