Chemistry 121 Oregon State University

Worksheet 4 Notes Dr. Richard L Nafshun

1. Name: (a) Ca(NO3)2

calcium nitrate

(b) AlN

aluminum nitride

aluminum oxide

(d) NaCN

sodium cyanide

(e) (NH4)2S

ammonium sulfide

(f) Na2S

sodium sulfide

(g) NH4OH

ammonium hydroxide

(h) CaO

calcium oxide

(i) KBr

potassium bromide

(j) MgSO4

magnesium sulfate

(k) NiCl2

nickel(II) chloride

(l) PbS2

lead(IV)sulfide

(m) CuCl

copper(I) chloride

(n) CuCl2

copper(II) chloride

(o) Fe2O3

iron(III) oxide

(p) FeO

iron(II) oxide

2. Give the chemical formulae for the following ionic compounds:

(a) aluminum sulfide

Al2S3

(b) sodium sulfide

Na2S

(c) sodium sulfate

Na2SO4

(d) sodium hydroxide

NaOH

(e) aluminum cyanide

Al(CN)3

(f) calcium nitrate

Ca(NO3)2

(g) cesium phosphate

Cs3PO4

(h) cerium(III) chloride

CeCl3

(i) lithium acetate

LiCH3COO

(j) copper(II) carbonate

CuCO3

(k) iron(II) phosphate

Fe3(PO4)2

(l) iron(III) oxide

Fe2O3

3. Consider a red light that has a wavelength of 710.2 nm. Express this wavelength in cm. Express this wavelength in km. Express this wavelength in inches.

710.2 nm = 7.102 x 10-5 cm

7.102 x 10-5 cm = 7.102 x 10-10 km

7.102 x 10-5 cm = 2.796 x 10-5 inch

4. A student measures a mass to be 2.55 x 103 kg. Express this mass in mg.

2.55 x 103 kg = 2.55 x 109 mg

5. What is a heterogeneous mixture?

A mixture that is different throughout.

What is a homogeneous mixture?

A mixture that is the same throughout.

How many elements are there?

About 112 to 114.

Approximately how many compounds have cataloged and characterized?

About 17 million.

Is heptane one of them? Yes. C7H16.

Is aluminum chloride one of them? Yes. AlCl3.

6. Determine the number of protons, neutrons, and electrons in each of the following:

Species / p / n / e-
187Os / 76 / 111 / 76
198Au / 79 / 119 / 79
198Au3+ / 79 / 119 / 76
198Au+ / 79 / 119 / 78
210Pb / 82 / 128 / 82
210Pb2+ / 82 / 128 / 80
7Li / 3 / 4 / 3
7Li+ / 3 / 4 / 2
16O / 8 / 8 / 8
16O2- / 8 / 8 / 10
18O / 8 / 10 / 8
18O2- / 8 / 10 / 10
19F / 9 / 10 / 9
19F- / 9 / 10 / 10
238U / 92 / 146 / 92

7. List three isotopes of hydrogen. Identify the number of protons, neutrons, and electrons in each. Identify the number of protons, neutrons, and electrons in 1H+.

Species / p / n / e-
1H / 1 / 0 / 1
2H / 1 / 1 / 1
3H / 1 / 2 / 1
1H+ / 1 / 0 / 0

8. Write the formula and name a compound composed of calcium and fluorine.

CaF2 is calcium fluoride

9. Write the formula and name a compound composed of aluminum, sulfur, and oxygen.

Al2(SO4)3 is aluminum sulfate

10. Natural strontium consists of the following isotopes:

Isotope

Molar Mass, u

Percent Abundance

Strontium-84 / 83.913 / 0.56
Strontium-86 / 85.909 / 9.86
Strontium-87 / 86.909 / 7.00
Strontium-88 / 87.906 / 82.58

Calculate the molar mass of strontium.

The molar mass is the weighted average:

Molar mass = (83.913 g/mol)(0.0056) + (85.909 g/mol)(0.0986) +

(86.909 g/mol)(0.070) + (87.906 g/mol)(0.8258)

= 87.634 g/mol