General Chemistry Ch. 3

In the combustion analysis of 0.1127 g of glucose (C6H12O6), what mass, in grams, of CO2 would be produced?

0.1652 g

Phosphorus pentachloride, PCl5, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl5.

0.186 mol

Calculate the number of moles in 17.8 g of the antacid magnesium hydroxide, Mg(OH)2.

0.305 mol

Aluminum oxide, Al2O3, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al2O3.

0.4660 mol

Magnesium fluoride is used in the ceramics and glass industry. What is the mass of 1.72 mol of magnesium fluoride?

107 g

Copper(II) sulfate pentahydrate, CuSO4·5H2O, is used as a fungicide and algicide. Calculate the mass of oxygen in 1.000 mol of CuSO4·5H2O.

144.0 g

Calculate the molar mass of (NH4)3AsO4.

193.03 g/mol

A normal breath takes in about 1.0 L of air. Assuming that air has an average molar mass of 28.8 g, and that its density is 0.97 g/L, how many molecules of air do you take in with each breath?

2.0 × 1022

How many atoms are in a drop of mercury that has a diameter of 1.0 mm? (Volume of a sphere is 4r 3/3; density of mercury = 13.6 g/cm3)

2.1 × 1019

The number of hydrogen atoms in 0.050 mol of C3H8O3 is

2.4 X 10^23 H atoms

Calculate the molar mass of Ca(BO2)2·6H2O.

233.79 g/mol

What is the mass in grams of 0.250 mol of the common antacid calcium carbonate?

25.0 g

Determine the percent composition of potassium dichromate, K2Cr2O7.

26.58 % K, 35.35 % Cr, 38.07 % O

Calculate the molar mass of tetraphosphorus decaoxide, P4O10, a corrosive substance which can be used as a drying agent.

283.89 g/mol

Balance the following equation for the combustion of benzene: C6H6(l) + O2(g) -->H2O(g) + CO2(g)

2C6H6(l) + 15O2(g) → 6H2O(g) + 12CO2(g)

Balance the following equation: Ca3(PO4)2(s) + SiO2(s) + C(s)--> CaSiO3(s) + CO(g) + P4(s)

2Ca3(PO4)2(s) + 6SiO2(s) + 10C(s) → 6CaSiO3(s) + 10CO(g) + P4(s)

Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

3.227 × 1023 Cr atoms

Sulfur trioxide can react with atmospheric water vapor to form sulfuric acid that falls as acid rain. Calculate the mass in grams of 3.65 × 1020 molecules of SO3.

4.85 × 10^-2g

Calculate the number of oxygen atoms in 29.34 g of sodium sulfate, Na2SO4.

4.976 × 1023 O atoms

Household sugar, sucrose, has the molecular formula C12H22O11. What is the % of carbon in sucrose, by mass?

42.1 %

Calculate the mass in grams of 8.35 × 10^22 molecules of CBr4

46.0 g

Sodium bromate is used in a mixture which dissolves gold from its ores. Calculate the mass in grams of 4.68 mol of sodium bromate.

706 g

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass O. If its molar mass is between 94 and 98 g/mol, what is its molecular formula?

N2H4O4

Balance the following equation: UO2(s) + HF(l) --> UF4(s) + H2O(l)

UO2(s) + 4HF(l) → UF4(s) + 2H2O(l)

Calcium fluoride, CaF2, is a source of fluorine and is used to fluoridate drinking water. Calculate its molar mass. A. 118.15 g/mol B. 78.07 g/mol C. 99.15 g/mol D. 59.08 g/mol E. 50.01 g/mol

78.07 g/mol

Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO3)2.

87.0 g

Alkanes are compounds of carbon and hydrogen with the general formula CnH2n+2. An alkane component of gasoline has a molar mass of between 125 and 130 g/mol. What is the value of n for this alkane?

9

Balance the following equation: B2O3(s) + HF(l) --> BF3(g) + H2O(l)

B2O3(s) + 6HF(l) → 2BF3(g) + 3H2O(l)

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

BrF3

Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO2 and 0.226 g H2O. What is its empirical formula?

C4H3O2

Analysis of a carbohydrate showed that it consisted of 40.0 % C, 6.71 % H, and 53.3 % O by mass. Its molecular mass was found to be between 140 and 160 amu. What is the molecular formula of this compound?

C5H10O5

Balance the following equation: C8H18O3(l) + O2(g) --> H2O(g) + CO2(g)

C8H18O3(l) + 11O2(g) → 9H2O(g) + 8CO2(g)

Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO2 and 0.226 g H2O. If its molar mass is between 158 and 167 g/mol, what is its molecular formula?

C8H6O4

A compound containing chromium and silicon contains 73.52 mass percent chromium. Determine its empirical formula

Cr3Si2

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

H2NO2

Hydroxylamine hydrochloride is a powerful reducing agent which is used as a polymerization catalyst. It contains 5.80 mass % H, 20.16 mass % N, 23.02 mass % O, and 51.02 mass % Cl. What is its empirical formula?

H4NOCl