Chem 1010 Practice Test 1 For Full Credit - Must Show ✓ Solved

Chem 1010 Practice Test 1 For full credit you must show

A French exchange student has a height of 1.60 m. How many significant figures are in this measurement? Calculate and express the height of the student in the usual American way using feet and inches. A gasoline tanker transports about 11,000 gallons of fuel. What mass of gasoline is in a full tanker? (Density of gasoline = 0.75 kg/L, 1 L = 1.057 quart, 4 quarts = 1 gallon) A candlestick weighing 26 ounces is made of brass composed of 65% copper and 35% zinc. What is the mass of the candlestick in kilograms? What mass of zinc is in this candlestick? What mass of brass for candlesticks could be made from 155 kg of copper? Which of the terms element, compound, or mixture is correctly used for A, B, and C in the following sentence: Minor constituents of the {A} that constitutes our atmosphere include the {B} argon and the {C} carbon dioxide. Match each element with its symbol from this list: C, Ca, Cu. 18.2 g of zinc reacts with sulfur to produce 27.0 g of zinc sulfide as the only product. What mass of sulfur must have reacted with zinc? What Law of chemistry did you use to make the determination in part a? If 1.8 kg of zinc sulfide were decomposed, how much zinc could be produced, assuming none is lost in the process? What Law of chemistry did you use to make the determination in part c? Use the periodic table to answer various questions about elements. A neutral sulfur atom has 16 electrons. Write the full electron configuration for a neutral sulfur atom. How many valence electrons does a neutral sulfur atom have? Draw a Lewis dot symbol for a neutral sulfur atom. What is the charge on a sulfide ion? Cesium is an element in group 1 with the symbol Cs. What is the charge on a cesium ion? What is the formula of cesium sulfide? Mercury vapor lamps emit violet light with a wavelength of 436 nm. What is this wavelength in meters? What is the frequency (in hertz, Hz = per second) of light of this wavelength? Rock 103 broadcasts at 102.7 MHz. Calculate the energy of a single photon of this electromagnetic radiation. Halothane, a common general anesthetic with formula C2HBrClF3, has a boiling point of 50°C. What is 50°C in Fahrenheit? Use the atomic weights given on the periodic table to determine the formula weight of halothane in unified atomic mass units. Calculate the percentage by mass of fluorine in halothane. Explain the difference between a scientific law and a scientific theory. Explain the difference between a compound and a homogeneous mixture of elements using nitrogen, oxygen, and nitrous oxide (N2O) to illustrate your answer.

Paper For Above Instructions

Significant Figures and Conversion of Height

The height of the French exchange student is 1.60 meters, which contains three significant figures. This is because all non-zero digits are significant, and trailing zeros in the decimal portion are also significant (Baldwin, 2023). To convert the height into feet and inches, note that 1 inch is equal to 2.54 centimeters. First, we convert meters to centimeters: 1.60 m = 160 cm. Then, we convert centimeters to inches: 160 cm / 2.54 cm/inch = 62.99 inches. Finally, we convert inches into feet and inches: 62.99 inches = 5 feet 2.99 inches, or approximately 5 feet 3 inches.

Mass of Gasoline in Tanker

The gasoline tanker transports approximately 11,000 gallons. First, we need to convert gallons to liters. Knowing that 1 gallon = 3.78541 liters, we find that 11,000 gallons ≈ 41,635 liters. Given the density of gasoline is 0.75 kg/L, the mass of gasoline in the full tanker can be calculated as follows:

Mass = Density x Volume = 0.75 kg/L * 41,635 L = 31,226.25 kg. Therefore, the mass of gasoline is approximately 31,226 kg.

Mass of the Candlestick

The candlestick weighs 26 ounces. To convert this to kilograms, we first convert ounces to pounds: 26 ounces / 16 ounces/pound = 1.625 pounds. Then we convert pounds to kilograms using the conversion factor 1 kg = 2.205 pounds:

Mass = 1.625 pounds / 2.205 pounds/kg ≈ 0.738 kg. Hence, the mass of the candlestick is approximately 0.738 kg.

Mass of Zinc in the Candlestick

To determine the mass of zinc in the candlestick made of 65% copper and 35% zinc, we use the mass of the candlestick (0.738 kg). The mass of zinc can be calculated as:

Zinc mass = 0.738 kg * 0.35 = 0.2583 kg or approximately 0.258 kg.

Mass of Brass from Copper

To find out how much brass can be made from 155 kg of copper, we need to consider the composition of brass. Since brass consists of 65% copper, we can assign variable brass mass (B):

Let B = Brass mass

0.65B = 155 kg (from copper) → B = 155 kg / 0.65 = 238.46 kg of brass can be made from 155 kg of copper.

Identifying Elements and Compounds

A: Mixture; B: Element (argon); C: Compound (carbon dioxide). The terms relate to their chemical nature as follows: argon is a pure element, carbon dioxide is a compound, and the mix of these along with various gases makes up the atmosphere.

Calculating Reactor Masses

In chemical reaction, the mass of sulfur that reacted with 18.2 g of zinc can be deduced using the law of conservation of mass which states that mass can neither be created nor destroyed.

Mass of sulfur = Mass of zinc sulfide - Mass of zinc = 27.0 g - 18.2 g = 8.8 g.

Law of Chemistry

The law used here is the Law of Conservation of Mass. For the decomposition of 1.8 kg of zinc sulfide, the mass of zinc produced can be found using stoichiometry, leading us to expect about 1.8 kg of zinc if none is lost, adhering to the same conservation law.

Periodic Table Questions

Using the periodic table, we find that:

  • Atomic number of boron = 5
  • Atomic weight of iron ≈ 55.85 u
  • Noble gas in the first period = Helium
  • Group 15 (5A) element in the third period = Phosphorus (P)
  • Neutral magnesium atom has 12 electrons.
  • Carbon-14 (14C) has 8 neutrons (14 - 6 = 8).

Electron Configuration of Sulfur

A neutral sulfur atom has 16 electrons, and its full electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁴. It has 6 valence electrons (from the third period p-orbital). The Lewis dot structure represents these electrons:

:

S: (showing the valence electrons around sulfur).

The charge of a sulfide ion (S²⁻) indicates it has gained two electrons. Cesium (Cs), located in group 1, forms a cation with a +1 charge (Cs⁺). The formula for cesium sulfide is Cs₂S.

Electromagnetic Radiation

The violet light emitted by mercury vapor lamps has a wavelength of 436 nm (nanometers), which converts to meters as follows:

436 nm = 436 x 10⁻⁹ m = 4.36 x 10⁻⁷ m. To find the frequency:

Frequency (ν) = Speed of light (c) / Wavelength (λ) = 2.998 x 10⁸ m/s / 4.36 x 10⁻⁷ m ≈ 6.88 x 10¹⁴ Hz.

Calculating Energy of a Photon

The energy of a single photon is calculated using Planck’s equation: E = hν, where h is Planck’s constant (6.626 x 10⁻³⁴ J.s):

E = (6.626 x 10⁻³⁴ J.s) x (6.88 x 10¹⁴ Hz) ≈ 4.56 x 10⁻¹⁹ J.

Halothane Properties

To convert the boiling point of halothane from Celsius to Fahrenheit:

F = (50°C × 9/5) + 32 = 122°F.

The formula weight of halothane (C₂HBrClF₃) can be determined using atomic weights: C = 12.01 g/mol, H = 1.008 g/mol, Br = 79.904 g/mol, Cl = 35.453 g/mol, and F = 18.998 g/mol.

Calculating the total: 2(12.01) + 1(1.008) + 1(79.904) + 1(35.453) + 3(18.998) = 130.00 g/mol.

The percentage by mass of fluorine is calculated:

%F = (mass of F in compound / total mass of compound) × 100 = (3 × 18.998 / 130.00) × 100 ≈ 43.46%.

Scientific Law vs Theory

A scientific law describes a consistent relationship observed in nature, while a theory provides an explanation for those observations based on compiled evidence (Popper, 2005). For example, Newton's Law of Universal Gravitation describes the gravitational attraction between masses, while the Theory of Evolution explains the diversity of life through natural selection.

Compound vs Homogeneous Mixture

A compound consists of two or more elements chemically bonded together, exhibiting properties different from the constituent elements. A homogeneous mixture, like a gas containing nitrogen and oxygen, retains the properties of its individual components without chemical bonding. Nitrous oxide (N₂O) is a compound formed by nitrogen and oxygen, showing distinct properties unlike either gas alone (Smith, 2021).

References

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