CHEM 211 Chapter 1 & 2 Homework questions
The average distance from Earth to the Sun is 150 megameters. What is that distance in meters?
1.5 × 108 m
A sample of iron ore, which consists of iron, oxygen, silicon, and carbon, is 33.2% Fe by weight, 24.2% O, 26.3% Si, and 16.3% C. In a 755 kg sample of the ore, how many kg of metalloids are there?
199 kg
The appropriate number of significant figures in the result of 15.234 - 15.208 is
2
At a pressure of one billionth (10 -9) of atmospheric pressure, there are about 2.7 × 10 10 molecules in one cubic centimeter of a gas. How many molecules is this per cubic meter?
2.7 × 10^16
A large pizza has a diameter of 15 inches. Express this diameter in centimeters.
38 cm
Which of the following correctly expresses 52,030.2 m in scientific notation?
5.20302 × 104 m
The mass of a sample is 550 milligrams. Which of the following expresses that mass in kilograms?
5.5 × 10 -4 kg
Kaolinite, a clay mineral with the formula Al 4Si 4O 10(OH) 8, is used as a filler in slick-paper for magazines and as a raw material for ceramics. Analysis shows that 14.35 g of kaolinite contains 8.009 g of oxygen. Calculate the mass percent of oxygen in kaolinite.
55.81 mass %
"Vinyl" plastic, also called PVC, is a polymer made from vinyl chloride, C 2H 3Cl. What is the percent composition of the chlorine in vinyl chloride?
56.72%
Which one of the following combinations of names and formulas of ions is incorrect?
ClO3- perchlorate
The ripening of fruit, once picked, is an example of physical change.
False
Iron (III) chloride hexahydrate is used as a coagulant for sewage and industrial wastes. What is its formula?
FeCl3·6H2O
Which of the following compounds is ionic?
MgCl2
Which one of the following combinations of names and formulas of ions is incorrect?
NO2- nitrate
Which one of the following combinations of names and formulas is incorrect?
NaHCO 3 sodium carbonate
Which of the following compounds is covalent?
PCl3
You prepare 1000. mL of tea and transfer it to a 1.00 quart pitcher for storage. Which of the following statements is true?
The pitcher will be completely filled and a small amount of tea will overflow.
An important aim in much chemical work is to use macroscopic measurements in order to gain an understanding of the microscopic world.
True
The number 6.0448, rounded to 3 decimal places, becomes 6.045.
True
Which of the following is a metalloid?
germanium, Ge, Z = 32
The colorless substance, MgF 2, is used in the ceramics and glass industry. What is its name?
magnesium fluoride
A red glaze on porcelain can be produced by using MnSO 4. What is its name?
manganese(II) sulfate
Which of the following is an extensive property of oxygen?
mass
The potential energy of a car moving on a level road does not depend on its speed.
true
If the price of gold at the morning fixing in London was $5310 per lb, what would a kilogram of gold have cost in £ (pounds)? (Assume an exchange rate of $1.00 = £0.545)
£6370
Which of the following is a chemical change?
broiling a steak on a grill
The result of (3.8621 × 1.5630) - 5.98 is properly written as
0.06
Given that 1 inch = 2.54 cm, 1 cm 3 is equal to
0.0610 in3
The density of mercury, the only metal to exist as a liquid at room temperature, is 13.6 g/cm 3. What is that density in pounds per cubic inch?
0.491 lb/in3
A flask has a mass of 78.23 g when empty and 593.63 g when filled with water. When the same flask is filled with concentrated sulfuric acid, H 2SO 4, its mass is 1026.57 g. What is the density of concentrated sulfuric acid? (Assume water has a density of 1.00 g/cm 3 at the temperature of the measurement.)
1.840 g/cm3
Select the answer that expresses the result of this calculation with the correct number of significant figures and with correct units. (look on homework)
105.2 g/cm
The S.I. prefix mega- (M) means
10^6
A sample of iron ore, which consists of iron, oxygen, silicon, and carbon, is 33.2% Fe by weight, 24.2% O, 26.3% Si, and 16.3% C. In a 755 kg sample of the ore, how many kg of metals are there?
251 kg
A dose of medication was prescribed to be 35 microliters. Which of the following expresses that volume in centiliters?
3.5 × 10-3 cL
The average distance between the Earth and the Moon is 240,000 miles. Express this distance in kilometers.
3.9 × l0 5 km
Lithium forms compounds which are used in dry cells and storage batteries and in high-temperature lubricants. It has two naturally occurring isotopes, 6Li (isotopic mass = 6.015121 amu) and 7Li (isotopic mass = 7.016003 amu). Lithium has an atomic mass of 6.9409 amu. What is the percent abundance of lithium-6?
7.503%
Which of the following correctly expresses 0.000007913 g in scientific notation?
7.913 × 10-6 g
Phosgene, COCl 2, was the first designed war gas. It was used with terrible effects during WWI. What mass percent chlorine is phosgene?
71.69%
Which one of the following statements about atoms and subatomic particles is correct?
A neutral atom contains equal numbers of protons and electrons.
Bud N. Chemist must determine the density of a mineral sample. His four trials yield densities of 4.77 g/cm 3, 4.67 g/cm 3, 4.69 g/cm 3, and 4.81 g/cm 3. Independent studies found the correct density to be 4.75 g/cm 3. Which of the following statements represents the best analysis of the data?
Bud's results have much greater accuracy than precision
Potassium permanganate is a strong oxidizer that reacts explosively with easily oxidized materials. What is its formula?
KMnO4
Which one of the following combinations of names and formulas of ions is incorrect?
S2- sulfate
The compound, (NH 4) 2S, can be used in analysis for trace amounts of metals present in a sample. What is its name?
ammonium sulfide
The compound, BaO, absorbs water and carbon dioxide readily and is used to dry gases and organic solvents. What is its name?
barium oxide
The substance, CaSe, is used in materials which are electron emitters. What is its name?
calcium selenide
Which of the following is not an S.I. base unit?
gram
What is the name of the acid formed when HBr gas is dissolved in water?
hydrobromic acid
What is the name of the acid formed when H 2S gas is dissolved in water?
hydrosulfuric acid
Which of the following activities is not a part of good science?
indulging in speculation
The S.I. base unit of mass is
kilogram
What is the name of the acid formed when HClO 4 liquid is dissolved in water?
perchloric acid
The substance, KClO 3, is a strong oxidizer used in explosives, fireworks, and matches. What is its name?
potassium chlorate
The compound, NaH 2PO 4, is present in many baking powders. What is its name?
sodium dihydrogen phosphate
What is the name of Na 2O?
sodium oxide
What is the name of P 4Se 3?
tetraphosphorus triselenide
Which of the following is a metal?
thallium, Tl, Z = 81
Rutherford bombarded gold foil with alpha (α) particles and found that a small percentage of the particles were deflected. Which of the following was not accounted for by the model he proposed for the structure of atoms?
the total mass of the atom
Which of the following represents the largest volume?
100mL
The appropriate number of significant figures in the result of 15.234 × 15.208 is
5
Which measurement is expressed to 4 significant figures?
62.40 g
Barium sulfate is used in manufacturing photographic paper. What is its formula?
BaSO4
