Chemistry 2nd semester exam final

What is the percent yield if the expected production of a chemical reaction is 1.2 g of H2O, but only 1.0 g is actually produced?

• A) 120%

• B) 83.33%

• C) 100%

• D) 0.83%

What typically occurs during an exothermic reaction?

• The system absorbs heat from the surroundings.

• The system releases heat into the surroundings.

• The temperature of the system remains constant.

• The reactants and products exchange electrons.

Tags

NGSS.HS-PS1-4

Using the following equation, determine the moles of sucrose (C12H22O11) produced given 100 g of O2: 12 CO2 + 11 H2O → C12H22O11 + 12 O2

• 0.26 moles

• 36 moles

• 3.1 moles

• 180 moles

Tags

NGSS.HS-PS1-7

Consider the reaction: 3 Fe + 4 O₂ → 2 Fe₂O₃. Determine the number of moles of iron (III) oxide (Fe₂O₃) produced when 6.0 moles of iron (Fe) react with excess oxygen.

• A) 4.0 moles

• B) 3.0 moles

• C) 2.0 moles

• D) 6.0 moles

Which of the following reactions is associated with the highest decrease in entropy?

• A) N2 (g) + 3 H2 (g) → 2 NH3 (g)

• B) H2O (s) → H2O (l)

• C) C (s) + O2 (g) → CO2 (g)

• D) 2 H2O (l) → 2 H2 (g) + O2 (g)

What is the concentration of a solution if 0.5 moles of sodium chloride are dissolved in 200 mL of solution?

• A) 0.25 M

• B) 2.5 M

• C) 5 M

• D) 1.25 M

Each beaker shown below contains 2.2 grams of iron and 1 liter of 3.0 M H₂SO₄ at STP. Which reaction will go to completion first and why?

• Beaker A because of a higher concentration level

• Beaker A because of increased surface area

• Beaker B because of a higher concentration level

• Beaker B because of increased surface area

Tags

NGSS.HS-PS1-5

Use the chart below to answer the following question. Which of these combinations will probably form a precipitate?

• Barium Carbonate

• Aluminum Bromide

• Copper (II) Acetate

• Ammonium Chloride

Tags

NGSS.HS-PS1-1

What are the empirical and molecular formulas of a compound that consists of 85% carbon (C) and 15% hydrogen (H)? The compound's experimental molar mass is 56 g/mol.

• C₂H₃ and C₄H₆

• C₃H and C₆H₂

• C₅H and C₁₀H₂

• CH₂ and C₄H₈

A biologist requires 150 mL of 1.5 M NaCl. What volume of 6 M NaCl must be diluted with water to achieve this concentration?

• 10 mL

• 37.5 mL

• 25 mL

• 50 mL