General Chemistry Answers

Wine goes bad soon after opening because the ethanol (CH3CH2OH) in it reacts with oxygen gas O2 from the air to form water H2O and acetic acid CH3COOH the main ingredient of vinegar.

What mass of oxygen gas is consumed by the reaction of 2.1g of ethanol?

Given the standard enthalpy changes for the following two reactions:

(1) 4C(s) + 5H₂(g)C₄H₁₀(g)...... ΔH° = -125.6 kJ

(2) C₂H₄(g)2C(s) + 2H₂(g)......ΔH° = -52.3 kJ

what is the standard enthalpy change for the reaction:

(3) 2C₂H₄(g) + H₂(g)C₄H₁₀(g)......ΔH° = ?

Driving from Santa Cruz to Black Rock City, NV in the Black Rock Desert is 393 miles. Yes that is where Burning Man is held. If your truck gets 15.0 mi/gal, and the density of octane (C₈H₁₈, gasoline) is 0.703 g/mL, how many pounds of carbon dioxide (CO₂) would be generated by the round trip to Black Rock City (786 miles total trip)? The balanced chemical equation is provided below. Remember to use the three key conversion factors to convert between SI and English systems of measure.

In which of the following species is the oxidation number of sulfur less than 6?

A. SO3

B. Na2SO4

C. SO2

Which of the following is a reduction half-reaction?

A. Zn → Zn2+ + 2e−

B. Na → Na+ + 1e−

C. 2H+ + 2e− → H2

How much H2SO4 is needed to neutralize 1 liter of a 0.50M solution of NaOH ?

A. 0.25 mol

B. 0.50 mol

C. 1.0 mol

Which of these solutions is the most basic?

A.[H+]=1x10−4 M

B.[OH−]=1x10−4 M

C. [H+] = 1 x 10−14 M

 Suppose a solution at 80 C contains 350 g sucrose/100 g of water. If the temperature decreased to 60o C, how much sugar would precipitate?

A solution of potassium nitrate was made by dissolving 100 g of solid in 200 mL of water at 40°C. The solution was then cooled to 20°C and as the solubility reduced, crystals of potassium nitrate precipitated from the solution.

Calculate the mass of solid potassium nitrate crystals that would be formed in the solution at 20 °C. Note: 1 mL of water equals 1 g of water 

Acetylene, C2H2, is a gas used in welding. The molar enthalpy of combustion for acetylene is -2599 kJ. A mass of 0.338 g C2H2(g) is combusted in a bomb calorimeter. Ifthe heat capacity of the calorimeter is 5.54 kJ/°C, what is the temperature increase ofthe bomb calorimeter?

Rutherford fired positively charged alpha particles at a thin sheet of gold foil. A small number of alpha particles were deflected, some of them at large angles. Which of the following does this observation support?

OPTIONS

• The nucleus occupies most of the space in an atom.
• Atoms contain a dense nucleus in the center.
• Atoms contain positive and negative charges.
• The electrons are found in discrete energy levels.