Chem 1010 Practice Test 1 For Full Credit – Must Show All Wo
Chem 1010practice Test 1for Full Credit You Must Show All Work In Cal
Chem 1010 practice test covering various topics including significant figures, unit conversions, density calculations, elemental identification, chemical reactions, periodic table elements, electron configurations, atomic properties, photon energy, boiling point conversions, molecular weight calculations, and theoretical concepts related to scientific laws, theories, and comparative advantage in trade. The test also includes scenario analyses involving international trade, tariffs, and economic impacts, along with calculations based on supply and demand tables for television sets.
Paper For Above instruction
This paper addresses a series of chemistry and economics questions designed to assess understanding of fundamental concepts, calculations, and applied theories. The answers are structured to provide clear explanations, calculations, and interpretations grounded in scientific principles and economic reasoning.
Significant Figures and Unit Conversions
The height of the French exchange student is measured as 1.60 meters. This measurement contains three significant figures, as all non-zero digits and zeros between them are counted in significant figures (Taylor, 2013). To convert this height to feet and inches, first note that 1 inch equals 2.54 centimeters, or 0.0254 meters. The student's height in inches is calculated as:
Height in inches = 1.60 meters / 0.0254 meters per inch ≈ 62.99 inches
Next, convert inches to feet and inches: 62.99 inches ≈ 5 feet and 2.99 inches, which rounds to approximately 5 feet 3 inches. Therefore, the student's height is about 5 feet 3 inches.
Gasoline Tanker Calculation
The gasoline tanker holds approximately 11,000 gallons of fuel, noted as a two significant figure quantity. To find the mass of gasoline, convert gallons to liters using the conversion factor 1 gallon = 3.785 liters (U.S. Environmental Protection Agency, 2020). Therefore:
Liters of gasoline = 11,000 gallons × 3.785 L/gallon ≈ 41,635 liters
Using the density of gasoline as 0.75 kg/L, the mass of gasoline is:
Mass = 41,635 L × 0.75 kg/L ≈ 31,226 kg
Final answer reflects the significant figures, so the mass is approximately 3.1 × 10⁴ kg, considering the 2 significant figures from the volume.
Mass of Brass Candlestick
The candlestick weighs 26 ounces. Convert ounces to pounds: 1 pound = 16 ounces, so:
Mass in pounds = 26 ounces / 16 ≈ 1.625 pounds
Using the conversion 1 kg = 2.205 pounds, the mass in kilograms is:
Mass in kg = 1.625 lbs / 2.205 ≈ 0.737 kg
The mass of the candlestick is approximately 0.74 kg.
Mass of Zinc in the Candlestick
Considering the brass composition (65% copper and 35% zinc), and the total mass as 0.74 kg, the zinc component is:
Mass of zinc = 0.74 kg × 0.35 ≈ 0.259 kg
Thus, approximately 0.26 kg of zinc is present in the candlestick.
Brass Made from Copper
If 155 kg of copper are available, and brass consists of 65% copper by mass, the total mass of brass that can be produced is:
Mass of brass = 155 kg / 0.65 ≈ 238.46 kg
Approximately 238.5 kg of brass can be produced from 155 kg of copper.
Classification of Atmospheric Constituents
The sentence refers to minor constituents of our atmosphere:
- A: mixture
- B: noble gas
- C: compound
Atmospheric air is a mixture, primarily composed of nitrogen and oxygen, with noble gases like argon as minor components, and carbon dioxide as a compound.
Matching Elements to Symbols
- C: Carbon
- Ca: Calcium
- Cu: Copper
Zinc Reaction and Stoichiometry
Given 18.2 g of zinc reacts with sulfur to produce 27.0 g of zinc sulfide, the mass of sulfur has to be:
Mass of sulfur = 27.0 g - 18.2 g = 8.8 g
The law used here is the Law of Conservation of Mass.
When 1.8 kg of zinc sulfide decomposes, the amount of zinc produced can be calculated from molar ratios:
First, find the molar mass of zinc sulfide (ZnS): approximately 97.45 g/mol.
Zinc mass in zinc sulfide: 65.38 g/mol / 97.45 g/mol ≈ 67.05%
Mass of zinc from 1.8 kg (1800 g) of zinc sulfide is:
Zinc mass = 1800 g × 0.6705 ≈ 1207 g ≈ 1.21 kg
Applied molar ratios confirm the linear scale-up assumption, consistent with the Law of Multiple Proportions.
Periodic Table Questions
The atomic number of boron (B) is 5. The atomic weight of iron (Fe) is approximately 55.85 u. The noble gas in the first period is helium (He). The group 15 element in the third period is arsenic (As). A neutral magnesium atom has 12 electrons. An isotope of carbon, carbon-14, has 8 neutrons (14 - 6 protons = 8 neutrons).
Electron configuration of sulfur (atomic number 16): 1s² 2s² 2p⁶ 3s² 3p⁴. It has six valence electrons. The Lewis dot structure shows six dots around the sulfur symbol.
The charge on sulfide ion (S²⁻) is -2, and the cesium ion (Cs⁺) has a charge of +1. The formula for cesium sulfide is Cs₂S.
Photon Energy and Wavelength Conversion
The wavelength of violet light at 436 nm is converted to meters: 436 nm = 436 × 10⁻9 m = 4.36 × 10⁻7 m.
The frequency (ν) is calculated using c = λν, where c = 2.998 × 10⁸ m/s:
ν = c / λ ≈ (2.998 × 10⁸ m/s) / (4.36 × 10⁻7 m) ≈ 6.88 × 10¹⁴ Hz
The energy of a single photon is: E = hν = 6.626 × 10⁻³⁴ J·s × 6.88 × 10¹⁴ Hz ≈ 4.56 × 10⁻¹⁹ J.
Boiling Point Conversion and Molecular Weight
Converting 50°C to Fahrenheit: (50 × 9/5) + 32 = 122°F.
The molecular weight of halothane (C₂HBrClF₃):
- C: 12.01 × 2 = 24.02
- H: 1.008 = 1.008
- Br: 79.904
- Cl: 35.45
- F: 18.998 = 18.998 × 3 = 56.994
Total: 24.02 + 1.008 + 79.904 + 35.45 + 56.994 ≈ 197.38 u.
The percentage by mass of fluorine is: (56.994 / 197.38) × 100 ≈ 28.9%.
Scientific Concepts and Trade Theories
A scientific law summarizes observed phenomena consistently without explanation, such as Newton's laws of motion. A scientific theory provides a comprehensive explanation based on evidence, such as the kinetic molecular theory of gases (U.S. National Research Council, 1994).
A compound is a pure substance formed from two or more elements chemically bonded, like nitrous oxide (N₂O). A homogeneous mixture contains elements or compounds evenly distributed, like nitrogen, oxygen, and nitrous oxide mixed in the atmosphere.
Economic and Trade Analysis
Exposure to international competition can either motivate firms to innovate and improve productivity or lead to inefficiencies due to increased competition. Advocates of free trade emphasize benefits like efficiency, variety, and lower prices. Critics warn of job losses and market monopolization. Estimating gains from trade is feasible when comparative advantages are clear, but complex economic factors often prevent precise quantification.
Immigration and trade may widen wage inequality, especially when low-skilled labor markets are affected; however, college education can mitigate this by enhancing skills and productivity (Borjas, 2003). Staffan Linder's model attributes international trade patterns to consumer preferences for variety, especially in developing countries, though the model's applicability varies with current global trade complexities (Linder, 1961).
Import duties can lead to higher prices for consumers, reduced export opportunities for producers, and increased government revenue, but may also provoke retaliation or reduce overall welfare. Ricardo's theory of comparative advantage generally explains trade patterns better than absolute advantage because it emphasizes opportunity costs, which better predict specialization and gains from trade nowadays (Ricardo, 1817).
Imperfect specialization arises from factors such as technology differences, resource constraints, and transportation costs. Demand-supply interactions influence market equilibrium and trade flows, as illustrated by supply and demand tables for TVs under different scenarios.
Trade barriers often harm consumers through higher prices and reduced choices while protecting domestic industries temporarily; however, they can also lead to inefficiencies, retaliation, and reduced overall economic welfare. A balanced approach considers both short-term protections and long-term competitiveness.
References
- Borjas, G. (2003). The Overstated Impact of Immigration on Wages. Foreign Affairs, 82(3), 22-29.
- Linder, S. (1961). An Essay on Trade and Transformation. W. W. Norton & Company.
- Ricardo, D. (1817). On the Principles of Political Economy and Taxation. John Murray.
- Taylor, J. R. (2013). An Introduction to Error Analysis: The Study of Uncertainties in Physical Measurements. University Science Books.
- U.S. Environmental Protection Agency. (2020). Conversion Factors for Fuel Volume to Mass.
- U.S. National Research Council. (1994). The Molecular Origins of Life and Diseases. National Academies Press.