QA 3 Online Review

Students conduct a lab that requires them to use approximately 0.5 grams of a nickel compound. One student takes too much of the compound and has some left over. Which of the following is the correct procedure for handling the leftover compound?

• Pour the leftover compound into the sink.

• Dispose of the leftover compound in the normal trash.

• Ask the teacher how to dispose of any leftover compound.

• Place all the leftover compound back in its original container.

What is the electron configuration for manganese, atomic number 25?

• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰

• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵

• 1s² 2s² 2p⁶ 3s² 3p⁶

A student burns 1.50 mol C₃H₈ according to the following reaction:

C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O

How many grams of carbon dioxide, CO₂, are produced?

• 44 g

• 66 g

• 132 g

• 198 g

In the reaction 2 H₂ + O₂ → 2 H₂O what is the mole ratio of hydrogen(H₂) to water(H₂O)?

• 2:2

• 2:1

• 1:2

• 4:4

How many molecules are in 4.62 moles of nitric acid (HNO₃)?

• 1.33 x 10²³

• 6.02 x 10²³

• 2.78 x 10²⁴

• 8.34 x 10²⁴

In the reaction A + B → C + D, if element B is in excess, then:

• A is the limiting reactant.

• B is the limiting reactant.

• C is the limiting reactant.

• Both A and B are limiting reactants.

Which of the following is a single replacement reaction?

• CaCO₃(s) ↔ CaO(s) + CO₂(g)

• 4 Al(s) + 3 O₂(g) ↔ 2 Al₂O₃(s)

• Mg(s) + 2 HCl(aq) ↔ H₂(g) + MgCl₂(aq)

• 2 C₄H₁₀(g) + 13 O₂(g) ↔ 8 CO₂(g) + 10 H₂O(g)

The chemical equation represents a reaction between ammonia and oxygen to form nitrogen monoxide and water.

4 NH₃(g) + 5 O₂(g) → 4 NO(g) + 6 H₂O(g)

What is the limiting reagent when a 2.00 g sample of ammonia(NH₃) is mixed with 4.00 g of oxygen(O₂)?

• ammonia (NH₃)

• oxygen (O₂)

• nitrogen monoxide (NO)

• water (H₂O)

The equation for the synthesis of water is given below.

2 H₂ + O₂ → 2 H₂O

How many grams of oxygen gas(O₂) are needed to produce 36.0 grams of water(H₂O)?

• 9 grams

• 16 grams

• 32 grams

• 40 grams

What are the coefficients that would correctly balance this equation?

____Zn + ____K₂CrO₄ → ____K + ____ZnCrO₄

• 2, 1, 2, 1

• 1, 2, 3, 1

• 1, 2, 1, 2

• 1, 1, 2, 1