The typical temperature in a hospital room is set at 23.5 °C

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[35] The typical temperature in a hospital room is set at 23.5 °C. What is that temperature in degrees Fahrenheit (°F)? [36] Determine the mass of Ca(HCO
)
the following substance in amu (u) [37] Consider this thermochemical equation: 2CO(g) + O
(g) ? 2CO
(g) ?H = -565 kJ Is it exothermic or endothermic? How much energy is given off or absorbed? [38] How many protons, electrons and neutrons are in
Fe
? Protons (p) electrons (e) neutrons (n) [39] Give the proper formula for each name Iron(III)Chloride Potassium sulfate Dinitrogen pentoxide [40] Give the proper name for each molecule NO CS
Al
O
Extra Credit: 5 points (Questions can be from any chapter, following are just examples) 1. How many joules are needed to melt 15.0 g of ice at 0 °C? (Heat of fusion = 334 J/g) 2. Perform the following conversion: 60.0 km/hr to m/s

The Correct Answer and Explanation is:

[35] Convert 23.5 °C to °F

Use the formula: °F=(°C×95)+32°F = (°C \times \frac{9}{5}) + 32 °F=(23.5×95)+32=74.3°F°F = (23.5 \times \frac{9}{5}) + 32 = 74.3°F

✅ Answer: 74.3 °F

[36] Determine the mass of Ca(HCO₃)₂ in amu (u)

Find the molar mass by summing atomic masses (approximate values):

  • Ca = 40.08 u
  • H = 1.01 u
  • C = 12.01 u
  • O = 16.00 u

Mass of Ca(HCO₃)₂=40.08+2(1.01+12.01+3×16.00)=40.08+2(1.01+12.01+48.00)=40.08+2(61.02)=40.08+122.04=162.12 u\text{Mass of } \text{Ca(HCO₃)₂} = 40.08 + 2(1.01 + 12.01 + 3 \times 16.00) = 40.08 + 2(1.01 + 12.01 + 48.00) = 40.08 + 2(61.02) = 40.08 + 122.04 = 162.12\ \text{u}

✅ Answer: 162.12 amu

[37] Thermochemical Equation:

2CO(g)+O2(g)→2CO2(g)ΔH=−565 kJ2CO(g) + O₂(g) \rightarrow 2CO₂(g) \quad \Delta H = -565\ \text{kJ}

  • Negative ΔH ⇒ Exothermic (releases heat)

✅ Answer: Exothermic; 565 kJ is given off

[38] Number of Protons, Electrons, and Neutrons in Fe (Iron)

For neutral Fe-56 (most common isotope):

  • Atomic number = 26 ⇒ 26 protons, 26 electrons
  • Mass number = 56 ⇒ 56 – 26 = 30 neutrons

✅ Answer:

  • Protons: 26
  • Electrons: 26
  • Neutrons: 30

[39] Give the proper formula:

  • Iron(III) Chloride → Fe³⁺ + 3Cl⁻ → FeCl₃
  • Potassium sulfate → K⁺ and SO₄²⁻ → K₂SO₄
  • Dinitrogen pentoxide → N₂O₅

✅ Answer:

  • Iron(III) Chloride: FeCl₃
  • Potassium sulfate: K₂SO₄
  • Dinitrogen pentoxide: N₂O₅

[40] Name the following molecules:

  • NO → Nitrogen monoxide
  • CS₂ → Carbon disulfide
  • Al₂O₃ → Aluminum oxide

✅ Answer:

  • NO: Nitrogen monoxide
  • CS₂: Carbon disulfide
  • Al₂O₃: Aluminum oxide

🔥 Extra Credit

1. How many joules to melt 15.0 g of ice at 0 °C?

q=m×ΔHfus=15.0 g×334 J/g=5010 J\text{q} = m \times \Delta H_{\text{fus}} = 15.0\ \text{g} \times 334\ \text{J/g} = 5010\ \text{J}

✅ Answer: 5010 J

2. Convert 60.0 km/hr to m/s

60.0 km/hr=60.0×1000 m1 km×1 hr3600 s=600003600=16.67 m/s60.0\ \text{km/hr} = 60.0 \times \frac{1000\ \text{m}}{1\ \text{km}} \times \frac{1\ \text{hr}}{3600\ \text{s}} = \frac{60000}{3600} = 16.67\ \text{m/s}

✅ Answer: 16.67 m/s

📘 Explanation of Key Concepts (Condensed Version)

✅ Temperature Conversion

Temperature in Celsius (°C) can be converted to Fahrenheit (°F) using: °F=(°C×95)+32°F = \left(°C \times \frac{9}{5}\right) + 32

This is important for comparing medical, scientific, or weather measurements across systems (metric vs imperial).

✅ Atomic Mass / AMU

Atomic Mass Unit (amu or u) measures mass on the atomic scale. To calculate a compound’s mass in amu:

  1. Multiply each atom’s atomic mass by how many are in the formula.
  2. Sum all components.

✅ Thermochemistry: Endothermic vs Exothermic

  • Exothermic: Releases energy (ΔH < 0)
  • Endothermic: Absorbs energy (ΔH > 0)
    In this question, ΔH = -565 kJ, meaning energy is released during the combustion of CO.

✅ Subatomic Particles

  • Protons determine the element’s identity.
  • Electrons equal protons in a neutral atom.
  • Neutrons = mass number − atomic number.

Fe (Iron), atomic number 26, most common isotope Fe-56:

  • 26 protons
  • 26 electrons
  • 30 neutrons

✅ Chemical Formulas

  • Ionic Compounds: Combine cations and anions in ratios that balance the charges.
    • Iron(III) = Fe³⁺, Chloride = Cl⁻ → FeCl₃
  • Molecular Compounds: Use prefixes to denote atom counts.
    • Dinitrogen pentoxide = N₂O₅

✅ Molecular Naming

Rules for molecular naming (nonmetals):

  • Use prefixes (mono-, di-, tri-, etc.)
  • Second element ends in “-ide”

Examples:

  • NO → Nitrogen monoxide
  • CS₂ → Carbon disulfide
  • Al₂O₃ → Aluminum oxide (ionic compound; no prefixes)

✅ Phase Change Energy

To melt ice: q=m×ΔHfusionq = m \times \Delta H_{\text{fusion}}

Heat of fusion is the energy required to melt 1 gram of a substance without temperature change. For water, it’s 334 J/g.

✅ Unit Conversion

Use conversion factors: 60.0 km/hr×1000 m1 km×1 hr3600 s=16.67 m/s60.0\ \text{km/hr} \times \frac{1000\ \text{m}}{1\ \text{km}} \times \frac{1\ \text{hr}}{3600\ \text{s}} = 16.67\ \text{m/s}

Unit analysis is crucial to solving any physics or chemistry problem involving different measurement systems.

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