#47 Give three common ways that matter is measured. Give examples of each

Counting: Example, counting sheep

Volume: Example: estimating the #of jelly beans in a large jar.

Mass: Example: Weighing out some NaCl.

#48 Name the representative particleof each substance:

a. oxygen gas O2 (a molecule)

b. sodium sulfide Na2S (a formula unit)

c. sulfur dioxide SO2 (a molecule)

d. potassium K (an atom)

#49 How many hydrogen atoms arein a representative particle of each substance?

a. Al(OH)3 3

b. H2C2O4 2

c. (NH4)2HPO4 9

d. C4H10O 10

#50 Which contains more molecules:1.00 mole H2O2 , 1.00 mole of C2H6,or 1.00 mole CO?

They all contain exactly the same:

6.02 x 1023 molecules

#51 Which contains more atoms:1.00 mole of H2O2 , 1.00 mole of C2H6,or 1.00 mole of CO?

Since H2O2 contains 4 atoms permolecule, C2H6 contains 8 atomsper molecule, and CO only 2 atomsper molecule;1 mole of C2H6 contains the most atoms (6.02 x 1023 times 8)

#52 Find the number of represent-ative particles in each substance:

a. 3.00 moles Sn = (6.02 x 1023 times 3)

b. 0.400 moles KCl = (6.02 x 1023 times .4)

c. 7.50 moles SO2 = (6.02 x 1023 times 7.5)

d. 4.80 x 10-3 moles NaI = (6.02 x 1023 times .0048)

#53 Calculate the molar massof each substance:a. H3PO4 = 98.0 g/moleb. N2O3 = 76.0 g/molec. CaCO3 = 100.1 g/moled. (NH4)2SO4 = 132.1 g/molee. C4H9O2 = 89.0 g/molef. Br2 = 159.8 g/mole

#54 Calculate the mass of 1.00 moleof each of these substances

the mass on one mole of somethingis just its molar mass…

a. SiO2 = 60.1 g/moleb. N2 = 28.0 g/molec. Fe(OH)3 = 106.8 g/moled. Cu = 63.5 g/mole

#58 How many moles is each of the following:In each of these you simply divide by the molar mass of each compound

a. 15.5 g SiO2 15.5 g x 1 mole (28.1 + 32) = .258 moles

b. .0688 g AgCl 4.80x10-4 moles

c. 79.3 g Cl2 1.12 mole

d. 5.96 g KOH .106 mole

e. 937 g Ca(C2H3O2) 5.93 mole

f. .800 g Ca .020 mole

#59 Find the mass of each substance.

a. 1.50 mole C5H12 = 108 grams

In each of these you multiply by the molar mass

b. 14.40 mole F2 = 547 grams c. .780 mole Ca(CN)2 = 71.8 grams

d. 7.00 mole H2O2 = 238 grams

e. 5.6 mole NaOH = 224 grams

f. 3.21 x 10-2 mole Ni = 1.88 grams

#60 Calculate the volume of each of the following gases at STP.

The volume of any gas at STP is22.4 liters per mole

a. 7.6 moles Ar x 22.4 liters = 1.7 x 102 liter

1 mole

b. .44 moles C2H6 x 22.4 liters = 9.9 liter

1 mole

#61 What is the density of each of the following gases at STP.(density is in units of grams/liter)

a. C3H8 The molar mass is: (12x3 +8) = 44

x 1 mole = 1.96 g 22.4 liters liter

b. Ne

44 g1 mole

The molar mass is: 20.220.2 g1 mole

x 1 mole = .902 g 22.4 liters liter

#61 What is the density of each of the following gases at STP.(density is in units of grams/liter)

c. NO2 The molar mass is: (14+32) = 46

x 1 mole = 2.05 g 22.4 liters liter

46 g1 mole

#62 Find each of the followingquantities:a. the volume, in liters, of 835 g SO3

835 g x 1 mole x 1 80.1

22.4 liters = 1 mole

234 Liters SO3

#62 Find each of the followingquantities:b. the mass in grams, of a moleculeof aspirin (C9H8O4)

1 molecule x 1 mole x 1 6.02 x 1023 molecules

180 g = 2.99 x 10-22 grams1 mole

22.4 liters = 1 mole

#62 Find each of the followingquantities:c. The number of atoms in 5.78 molesNH4NO3

5.78 moles x 6.02 x1023 molecules 1 1 mole

9 atoms = 3.13 x 1025 atoms1 molecule NH4NO3

#63 Calculate the percent compositionof each compound.a. H2S

The total is: (1.0 x 2) + 32.1= 34.1

% comp. H is: 2.0 x 100 = 5.9% 34.1

% comp. S is: 32.1 x 100 = 94.1% 34.1

#63 Calculate the percent compositionof each compound.b. (NH4)2C2O4

The total is: (18.0 x 2) +24.0 + 64.0 = 124.0

% comp. N is: 28.0 x 100 = 22.6% 124.0

% comp. H is: 8.0 x 100 = 6.5% 124.0

% comp. O is: 64.0 x 100 = 51.6% 124.0

% comp. C is: 24.0 x 100 = 19.4% 124.0

#63 Calculate the percent compositionof each compound.c. Mg(OH)2

The total is: 24.3 +(17.0 x 2) = 82.6

% comp. Mg is: 24.3 x 100 = 41.7% 82.6

% comp. O is: 32.0 x 100 = 54.9% 82.6

% comp. H is: 2.0 x 100 = 3.4% 82.6

#63 Calculate the percent compositionof each compound.d. Na3PO4

The total is: (23.0 x 3) + 31.0 + 64.0 = 164.0

% comp. Na is: 69.0 x 100 = 42.1% 164.0

% comp. P is: 31.0 x 100 = 18.9% 164.0

% comp. O is: 64.0 x 100 = 39.0% 164.0