3.3.2 Stoichiometry and Chemical Equations Flashcards Preview

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Flashcards in 3.3.2 Stoichiometry and Chemical Equations Deck (12)
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1
Q

Stoichiometry and Chemical Equations

A
  • Balanced chemical equations relate reactants and products in moles.
  • Molar ratios from balanced chemical equations can be used as conversion factors.
2
Q

note

A
  • Balanced chemical equations can be considered to relate reactants and products in moles.
  • In this example, 1 mole of nitrogen gas (N2) reacts with 3 moles of hydrogen gas (H2) to produce 2 moles of ammonia (NH3).
  • The balanced chemical equation can be used to predict the number of moles of products one should expect from a given number of moles of reactant. For example, 9.4 moles of nitrogen can produce 19 moles of ammonia, while 13.3 moles of nitrogen can produce 26.6 moles of ammonia.
  • It can similarly be used to calculate the quantity of a second reactor that will be needed to completely react with the first.
  • The balanced chemical equation can be used once you’ve converted things to moles. Problem: How many grams of hydrogen gas are needed to react with 53.1 grams of nitrogen gas?
  • First, convert grams of nitrogen gas to moles of nitrogen gas by using the molar massof nitrogen gas.
  • Second, convert moles of nitrogen gas to moles of hydrogen gas by using the balanced chemical equation.
  • Finally, convert moles of hydrogen gas to grams of hydrogen gas by using the molar mass of hydrogen gas.
3
Q

Benzene, C6H6, is a component of gasoline. Which statement about the following balanced equation for the combustion of benzene is false?

2 C6H6 + 15 O2 → 12 CO2 + 6 H2O.

A

To produce 15 moles of carbon dioxide requires 12 moles of oxygen.

4
Q

What is the mass of oxygen produced from 0.25 moles of KClO3 according to the following reaction?

2KClO3 → 2KCl + 3O2

A

12 g

5
Q

Which statement about the following chemical reaction is not true?

3H2(g) + N2(g) → 2NH3(g)

A

1.00 g of nitrogen will react with excess hydrogen to produce 2.00 g of product.

6
Q

Which of the following expressions correctly sets up the calculation needed to determine the number of grams of KClO3 produced during the reaction of 0.150 moles of Cl2 in excess potassium hydroxide according to the following reaction?

3Cl2 + 6KOH → 5KCl + KClO3 + 3H2 O
A

0.150 mol C2 * 1mol KCLO3/3mol Cl2 * 122.548g KCLO3/1mol KCLO3

7
Q
Elemental tungsten (W) can be produced by the following reaction:
WO3(s) + 3H2(g) -> W(s) + 3H2O(l)

How many moles of tungsten form in the reaction of 0.0207 moles of WO3?

A

0.0207 mol

8
Q

Which of the following expressions is appropriate for use in determining the number of grams of FeCl3 produced from 6 moles of Cl2 in excess iron, as indicated in the following equation?

2Fe(s) + 3Cl2(g) → 2FeCl3(s)
A

6mol C2 * 2mol FeCl3/3mol CL2 * 162.2g FeCl3/1mol FeCl3

9
Q

How many moles of sulfur dioxide can be produced by burning 16 grams of sulfur in excess oxygen?

S8 + 8 O2 → 8 SO2
A

0.50 moles

10
Q

How many grams of hydrazine, N2H4, are produced from the reaction of 5.0 moles of N2 with an excess of H2, as shown in the following equation:

2H2(g) + N2(g) → N2H4(g)
A

160 g

11
Q

Using the following balanced chemical equation, calculate the number of grams of aluminum bromide (AlBr3 ) formed during the reaction of 1.50 moles of HBr in the presence of excess aluminum hydroxide.

3HBr(aq) + AL(OH)3(aq) -> ALBr3(aq) + 3H2O(l)

A
  1. grams
12
Q

What is the maximum amount of potassium chlorate, KClO3, used in fireworks, that can be produced from the reaction of 10.64 g of Cl2 and excess potassium hydroxide according the reaction below?
3CL2(g) + 6KOH(aq) -> 5KCL(aq) + KCLO3(aq) + 3H2O(1)

A

6.13 g

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