Chemistry Quiz

Which of the following formulas would have the molecular geometry of the structure shown below?

• XeF4

• SF4

• SiF4

• CF4

What is the molar mass of iron (3) hydroxide?

• 106.88 g/mol

• 72.86 g/mol

• 74.88 g/mol

• 184.56 g/mol

Which of the following conditions would NOT cause an increase in the concentration of the product of the equilibrium system: 2 CO (g) + O2 (g) → 2 CO2 (g) + 167 KJ

• addition of CO

• decrease in volume

• lower temperature

• decrease in pressure

An equilibrium mixture of SO2, O2, and SO gases at 1500 K is determined to consist of 0.344 mol/L SO2, 0.172 mol/L O2, and 0.56 mol/L SO3. What is the equilibrium constant for the system at this temperature? The balanced equation for this reaction is 2SO2(g) + O2(g) ↔ 2SO3 (g).

• 0.41

• 0.065

• 6.7

• 15

Which of the following changes to the system at equilibrium would result in an increase in the concentration of O2?

• An increase in the concentration of SO2 and an increase in the temperature.

• An increase in the concentration of SO2 and a decrease in the temperature.

• An increase in the concentration of SO3 and a decrease in the temperature.

• An increase in the concentration of SO3 and an increase in the temperature.

What is the percentage yield if 56.9 g of WO2 yields 41.4 g of tungsten?

• 83.4%

• 91.8%

• 57.7%

• 79.1%

If 155g of WO reacts with 25.0g of H2, how many grams of the excess reactant will remain after the reaction is completed?

• 4.13g

• 23.0g

• 21.0g

• 130.0g

A chemist carries out this reaction and obtains 11.4g of tungsten. If the percentage yield is 89.4%, what volume of hydrogen gas at STP was used?

• 1.55 L

• 4.66 L

• 1.24 L

• 3.73 L

How many moles of water will be produced from 3.72 g of WO, if the yield is 92.0%?

• a. 0.0481 mol

• b. 0.0523 mol

• c. 0.0443 mol

• d. 0.797 mol

Which of the following correctly represents the equilibrium constant expression for the reaction above?

• Keq[HBr] / [H2][Br2]

• Keq = [H2][Br2] / [HBr]2

• Keq = [HBr]2 / [H2][Br2]

• Keq = [H2][Br2]/[HBr2]