Chapter 12 Stoichiometry

An apple pie needs 5 large apples (A), 2 crusts (C) (top and bottom), and 1 tablespoon of cinnamon (Ci). The "balanced equation" that fit this recipe is?

• 5 A + 2 C + Ci ----> A₅C₂Ci

• A + 2 C + Ci ----> AC₂Ci

• 5 A + C + Ci ----> A₅CCi

• 5 A + 2 C + 2Ci ----> A₅C₂Ci₂

Two molecules of Hydrogen (H₂) react with one molecule of Oxygen(O₂) yields two molecules of water (H₂O). The balanced equation of this synthesis is

2H₂(g) + O₂(g) ---> 2 H₂O(l)

How many molecules of water are produced from 3.0 moles Oxygen?

• 2.0 x 10²³ molecules

• 6.0 x 10²³ molecules

• 6.0 x 10 ^-23 molecules

• 4.0 x 10^-23 molecules

Tags

NGSS.HS-PS1-7

Thermal decomposition of Mercury II, Oxide (HgO) can be represented for the following balanced equation:

2 HgO(s) ----> 2 Hg(l) + O₂(g)

How many moles of Mercury II, Oxide are needed to produce 5 moles of Oxygen?

• 10 moles

• 20 moles

• 5 moles

• 30 moles

Tags

NGSS.HS-PS1-7

The following balanced equation shows the formation of Silver Chloride (AgCl).

2 Ag(s) + Cl₂(g)---> 2 AgCl(s).

Calculate the mass of Silver (Ag) needed to react with Chlorine (Cl) that yields 8.4 g of Silver Chloride.

(Hint: Molar Masses: AgCl= 143.5 g/mol; Ag= 107.9 g/mol; Cl= 35.5 g/mol)

• 0.63 g

• 63 g

• 6.3 g

• 630 g

Calculate the number of liters (L) of Oxygen (O₂) needed to produce 1.5 L of Dinitrogen Trioxide (N₂O₃). Assume all gases are at the same conditions of temperature and pressure. (Hint: Molar Volume= 22.4 L)

2 N₂(g) + 3 O₂(g) ---> 2 N₂O₃(g)

• 22.5 L

• 2.25 L

• 0.225 L

• 225 L

A volume of 0.75 L of Hydrogen gas (H₂) at STP (standard temperature and pressure) was produced from the single-replacement reaction of Zinc (Zn) and Nitric Acid (HNO₃). Calculate the mass in grams of Zinc needed for this reaction. (Hint: Molar Volume= 22.4 L; Molar Mass of Zn= 65.4 g/mol)

Zn(s) + 2 HNO₃(aq) ---> Zn(NO₃)₂ (aq) + H₂(g)

• 220 g

• 2.2 g

• 0.22 g

• 22.0 g

Tags

NGSS.HS-PS1-7

Lithium Nitride (Li₃N) reacts with water (H₂O) and Ammonia (NH₃) and Lithium Hydroxide (LiOH) are formed.

Li₃N(s) + 3 H₂O(l) ---> NH₃(g) + 3 LiOH (aq)

How many molecules of ammonia are formed when 36 g of water reacts?

(Hint: Molar Mass (H₂O) = 18 g/mol; Avogadro's Number = 6.02 x 10 ²³ particles)

• 6.02 x 10²³ molecules

• 4.01 x 10²³ molecules

• 4.01 x 10^-23 molecules

• 6.02 x 10^-23 molecules

Calculate the number of grams (g) of Nitrogen Dioxide (NO₂) that are produced from 1.5 moles of Nitrogen Monoxide (NO) according to the following balanced equation.

2 NO(g) + O₂(g) ---> 2 NO₂(g)

(Hint: Molar Masses: O₂= 32 g/mol; NO=30 g/mol; NO₂= 46 g/mol

• 69.0 g

• 690 g

• 6.90 g

• 0.690 g