Chemical Final Review Day 3

The balanced chemical equation for the observed reaction is shown.

2NaHCO₃ + CaCl₂ → CaCO₃ + CO₂ + 2NaCl + H₂O

Which statement BEST predicts the amount of product produced from a given

reactant when the second reactant is in excess?

• One mole of water (H₂O) is produced from every two moles of calcium chloride (CaCl₂)

• One mole of calcium carbonate (CaCO₃) is produced from every one mole of calcium chloride (CaCl₂)

• Two moles of carbon dioxide are produced from every two moles of sodium bicarbonate (NaHCO₃)

• Two moles of sodium chloride (NaCl) are produced from every one mole of sodium bicarbonate(NaHCO₃)

Tags

NGSS.HS-PS1-7

What are the coefficients needed to balance this chemical reaction to show that

matter is conserved?

Fe + Cl₂ → FeCl₃

• 1, 1, 1

• 2, 3, 2

• 3, 2, 2

• 4, 2, 2

Tags

NGSS.HS-PS1-7

This is the balanced chemical equation for the reaction that produces ammonia

(NH3) from nitrogen (N2) and hydrogen (H2).

N₂(g) + 3H₂(g) → 2NH₃(g)

How many moles of ammonia (NH3) would be produced if 2.5 moles of

nitrogen (N2) reacted with excess hydrogen (H2)?

• 1.3 mol NH3

• 2.5 mol NH3

• 5.0 mol NH3

• 7.5 mol NH3

Tags

NGSS.HS-PS1-7

This balanced equation shows that ​ (a)   mole(s) of aluminum (Al) react with ​ (b)   mole(s) of oxygen (O2) to yield ​ (c)   mole(s) of aluminum oxide (Al2O3). If a chemist wanted to produce 4 moles of aluminum oxide (Al2O3), she would need to start with ​ (d)   moles of aluminum (Al) and ​ (e)   moles of oxygen (O2).

• 4
• 3
• 2
• 8
• 6
• 1
• 5
• 7

What does the limiting reactant do to a reaction?

• it decreases the speed of the reaction

• it increases the speed of the reaction

• it starts the reaction once it is added

• it stops the reaction once it runs out

What is the definition of a reactant?

• Evidence that a chemical reaction has taken place

• New substance formed in a chemical reaction

• A substance that starts a chemical reaction

• Numbers placed in front of chemical formulas

For the reaction below, if you start with 5.0 mol of Zn and 5.0 mol of HCl, what

is your excess reactant?

Zn + 2HCl → ZnCl₂ + H₂

• HCl

• Zn

• H₂

• ZnCl₂

Lead(II) Sulfide, PbS, reacts with 0.900 moles of oxygen gas. How much

lead(II) oxide, PbO, would be produced by this reaction?

2PbS + 3O₂ → 2PbO + 2SO₂

• 0.600 moles

• 0.450 moles

• 1.80 moles

• 0.900 moles

Tags

NGSS.HS-PS1-7

Through calculations you determined a theoretical yield of 2.05 g of salt. If

your actual yield in the lab was 1.85 g, what was your percent yield?

• 185%

• 110%

• 90%

• 20%

Which correctly describes the trends on the Periodic Table?

• Ionization energy increases, and atomic radius decreases across a period.

• Ionization energy increases, and atomic radius increases down a group.

• Ionization energy decreases, and atomic radius increases across a period. 

• Ionization energy decreases, and atomic radius decreases down a group.