The density of an alcohol is 0.788 g/mL. What volume in microliters, μL, will correspond to a mass of 20.500 mg?

Step 1: Convert density from g/mL to g/L; 0.807 g/mL is equivalent to 807 g/L. Step 2: Calculate Moles of N₂; Density = Mass / Volume, or Mass = Density × Volume. Plugging in values, Mass = 807 g/L × 1 L gives us Mass = 807 g. Similarly, Moles = Mass / M.mass, which leads to Moles = 807 g / 28 g.mol⁻¹, giving us Moles = 28.82 moles. Step 3: Apply the Ideal Gas Law to determine Volume of gas occupied; P V = n R T, thus V = n R T / P. Remember to convert temperature to Kelvin (25 °C + 273 = 298 K). Hence, V = (28.82 mol × 0.08206 atm.L.mol⁻¹.K⁻¹ × 298 K) ÷ 1 atm, resulting in V = 704.76 L.

The accurate choice is the final one.

Oxygen and Nitrogen are the most alike among the listed elements due to their proximity in the periodic table. While this reasoning may not be particularly robust, these two elements share certain similarities. They are both classified as non-metals, exhibit high electronegativity, exist as diatomic gases in their elemental forms, contain a similar number of valence electrons, and generally act as oxidizing agents. Although Oxygen and Chlorine also show similarities, they are not as closely related as Oxygen and Nitrogen.

Answer: Mixture: Blood, Self raising flour,muesli,dyes, milk, tea, air, bronze

Pure substance: Copper wire, distilled water, table salt, oxygen.

Explanation:

A mixture is a substance composed of two or more compounds which are chemically independent and keep their individual chemical properties.

Examples: Blood, Self raising flour,muesli,dyes, milk, tea, air, bronze

A pure substance is defined as something with a uniform and constant composition and is called a pure substance.

Examples: Copper wire, distilled water, table salt, oxygen.

Correct answer:

C) Ca(OH)2

Note: The listed options in the question are incorrect. The accurate selections are shown below:

15. A total of 3.705 kg of substance Y is required to neutralize 100 moles of HCl(aq).

What might substance Y be? A Ca B CaO C Ca(OH)2 D CaCO3

Explanation:

A) Ca + 2HCl ---> CaCl2 + H2

Molar mass of Ca = 40 g/mol

The mass of Ca needed to neutralize 100 moles of HCl = 1/2 * 100 * 40 g = 2000g or 2 kg

B) CaO + 2HCl ---> CaCl2 + H2O

Molar mass of CaO = 56.1 g/mol

The mass of CaO needed to neutralize 100 moles of HCl = 1/2 * 100 * 56.1 g = 2805 g or 2.805 kg

C) Ca(OH)2 + 2HCl ---> CaCl2 + 2H2O

Molar mass of Ca(OH)2 = 74.1 g/mol

The mass of Ca(OH)2 necessary to neutralize 100 moles of HCl = 1/2 * 100 * 74.1 g = 3705 g or 3.705 kg

D) CaCO3 + 2HCl ---> CaCl2 + H2O + CO2

Molar mass of CaCO3 = 100 g/mol

The mass of CaCO3 required to neutralize 100 moles of HCl = 1/2 * 100 * 100 = 5000 g or 5.00 kg

Thus, the right choice is C.