Deck 8: Quantities in Chemical Reactions

Question 1

The primary greenhouse gas is carbon dioxide.

Answer 1

True

Question 2

Given the reaction: 2 Na(s)+ Cl₂(g)→ 2 NaCl(s)
The conversion factor for chlorine gas to sodium metal is: 2 mol Cl ≡ 2 mol Na

Answer 2

False

Question 3

Given the recipe: 2 cups flour + 1 egg + 3 oz blueberries → 4 muffins.
You can make 1 dozen muffins from 3 eggs.

Answer 3

True

Question 4

The percent yield is calculated by dividing the actual yield by the theoretical yield times 100.

Question 5

The limiting reactant is the product that is completely consumed in a chemical reaction.

Question 6

Before determining conversion factors,it is necessary to make sure the equation is properly balanced.

Question 7

One of the advantages of burning fossil fuels is that it produces O₂ for humans to breathe.

Question 8

Stoichiometry is a chemist's version of following a recipe.

Question 9

If it takes 2 cups of milk and 1 cup of cocoa mix to make three servings of hot chocolate,and you only have 1 cup of each,then you cannot make any hot chocolate.

Question 10

Global warming is due to the greenhouse gases preventing heat from Earth escaping into space.

Question 11

Given the reaction: 2 Na(s)+ Cl₂(g)→ 2 NaCl(s)
The conversion factor for chlorine gas to sodium chloride is: 1 mol Cl₂ ≡ 2 mol NaCl

Question 12

The theoretical yield is the amount of each reactant needed in order to make the maximum amount of product.

Question 13

The limiting reactant is the reactant that produces the maximum amount of product.

Question 14

The primary source for the rising carbon dioxide levels is respiration of the Earth's growing population.

Question 15

The conversion factor between mass and moles for a compound is the molar mass.

Question 16

The actual yield is the amount of product actually produced by a chemical reaction.

Question 17

Greenhouse gases affect the temperature of the earth by blocking sunlight from reaching earth.

Question 18

Given the chemical equation: 2 Ca + O₂ → 2 CaO,
if 2 moles of CaO are formed in this reaction,then 2 moles of O₂ must have reacted.

Question 19

The conversion factor for moles of carbon dioxide to mass of carbon dioxide is:
1 mole CO₂ ≡ 44.01 g.

Question 20

Given the recipe: 2 cups flour + 1 egg + 3 oz blueberries → 4 muffins.
You can make 9 muffins from 3.5 cups of flour.

Question 21

Given the recipe: 2 cups flour + 1 egg + 3 oz blueberries → 4 muffins
If you have 5 cups of flour,3 eggs and plenty of blueberries,the limiting reactant is the eggs.

Question 22

The percent yield can never be greater than 100%.

Question 23

Given the following generic equation,2 A + 3B → A₂B₃ △H rxn = +444 kJ,if you completely reacted 1 mole of compound A,the amount of heat absorbed would be 222 kJ.

Question 24

If the theoretical yield of a reaction is 144 grams and the actual yield of the reaction is 72 grams,the percent yield of the reaction is 200%.

Question 25

Given the recipe: 2 cups flour + 1 egg + 3 oz blueberries → 4 muffins
If you have 9 cups of flour,4 eggs and plenty of blueberries,the theoretical yield of muffins is 16.

Question 26

The limiting reactant determines what the actual yield is.

Question 27

For the following reaction you have 8 grams of hydrogen and 2 grams of oxygen.
2H₂ + O₂ → 2H₂O
The limiting reagent is the oxygen.

Question 28

The limiting reactant is not necessarily the reactant with the least mass.

Question 29

For the following reaction you have 8 grams of hydrogen and 2 grams of oxygen.
2H₂ + O₂ → 2H₂O
The theoretical yield of the reaction is 4 grams of water.

Question 30

The average global temperature depends on all factors EXCEPT what?

A)the amount of incoming sunlight
B)the amount of outgoing heat lost to space
C)the amount of greenhouse gases
D)the angle of the earth's surface in relation to the incoming sunlight
E)All of the above are factors.

Question 31

Which of the below statements about global warming is FALSE?

A)Some greenhouses gases are needed to keep the proper temperature balance.
B)Greenhouse gases prevent heat from leaving the earth.
C)Greenhouse gases allow sunlight to reach and heat the earth.
D)If the level of greenhouse gases increases,the temperature will decrease.
E)none of the above

Question 32

Since heat must be supplied to melt ice,the melting of ice is an endothermic process and so has a positive enthalpy value.

Question 33

The actual yield is the same as the theoretical yield if the reaction goes to completion and there is no loss of product.

Question 34

An exothermic reaction has a negative enthalpy of reaction.

Question 35

The primary cause of increasing greenhouse gases is:

A)the burning of vast amounts of rain forests.
B)the production of CO₂ by respiration.
C)the increased use of natural gas,petroleum and coal.
D)the release of CO₂ by decreasing solubility in the ocean.
E)none of the above

Question 36

When viewing a chemical equation,the limiting reactant can never be a chemical on the product side of the equation.

Question 37

Which of the following is TRUE?

A)Stoichiometry shows the numerical relationship between chemical quantities in a balanced chemical equation.
B)Stoichiometry allows prediction of the amounts of products that form in a chemical reaction based on the amounts of reactants.
C)Stoichiometry allows prediction of how much of the reactants are necessary to form a given amount of product.
D)All of the above are true.
E)None of the above are true.

Question 38

For the following reaction you have 8 grams of hydrogen and 2 grams of oxygen.
2H₂ + O₂ → 2H₂O
The excess reactant is the oxygen.

Question 39

Thermal energy flows into the reaction and out of the surroundings in an endothermic reaction.

Question 40

The enthalpy of reaction,△H _rxn,is the amount of thermal energy that flows when a reaction occurs at constant temperature.

Question 41

How many waffles can be made from 1 dozen eggs,assuming you have enough of all other ingredients?
Given: 2 cups flour + 3 eggs + 1 tbs oil → 4 waffles

A)48
B)12
C)4
D)16
E)not enough information

Question 42

Suppose two chemical reactions are linked together in a way that the O₂ produced in the first reaction goes on to react completely with Mg to form MgO in the second reaction. Reaction one:
2 KClO₃ → 3 O₂ + 2 KCl
Reaction two: 2 Mg + O₂ → 2 MgO
If you start with 4 moles of KClO₃,how many moles of MgO could eventually form?

A)2 moles
B)4 moles
C)6 moles
D)12 moles
E)none of the above

Question 43

How many grams of water are made from the reaction of 16.0 grams of oxygen gas?
Given the reaction: 2H₂ + O₂ → 2H₂O

A)18
B)9
C)36
D)16
E)not enough information

Question 44

Diatomic O₂ can react with the element magnesium to form magnesium oxide (MgO).The balanced chemical equation is:

If 4 moles of magnesium totally reacted with more than enough O₂,how many moles of MgO would be expected to form?

A)1 mole
B)2 moles
C)4 moles
D)8 moles
E)not enough information

Question 45

Given that 4 NH₃ + 5 O₂ → 4 NO + 6 H₂O,when 4.50 mol of H₂O are formed,the amount of NO formed is:

A)1.50 mol.
B)3.00 mol.
C)4.50 mol.
D)6.75 mol.
E)none of the above

Question 46

How many grams of sodium metal are needed to make 29.3 grams of sodium chloride? Given the reaction:
2Na + Cl₂ → 2NaCl

A)46.0
B)5.75
C)23.0
D)11.5
E)not enough information

Question 47

How many moles of water are made from complete reaction of 2.2 moles of oxygen gas with hydrogen gas?
Given the reaction:
2H₂ + O₂ → 2H₂O

A)4.4
B)1.1
C)2.2
D)3.3
E)not enough information

Question 48

How many moles of aluminum are needed to make 9 moles of molecular hydrogen? Given the reaction:
2 Al + 6 HCl → 2 AlCl₃ + 3H₂

A)2 moles
B)3 moles
C)4 moles
D)6 moles
E)none of the above

Question 49

How many moles of chlorine gas are needed to make 0.6 moles of sodium chloride? Given the reaction:
2Na + Cl₂ → 2NaCl

A)0.6
B)0.3
C)1.2
D)3.6
E)not enough information

Question 50

How many grams of chlorine gas are needed to make 117 grams of sodium chloride?
Given the reaction:
2Na + Cl₂ → 2NaCl

A)71.0
B)142
C)35.5
D)48.2
E)not enough information

Question 51

Diatomic N₂ can react with diatomic H₂ to form ammonia (NH₃).The balanced chemical equation is:

If 6 moles of H₂ totally reacted with more than enough N₂,how many moles of ammonia would be expected to form?

A)2 moles
B)3 moles
C)4 moles
D)6 moles
E)not enough information

Question 52

How many grams of water are made from the reaction of 4.0 grams of hydrogen gas?
Given the reaction: 2H₂ + O₂ → 2H₂O

A)18
B)72
C)36
D)4.5
E)not enough information

Question 53

How many eggs are needed to make 1 dozen waffles,assuming you have enough of all other ingredients?
Given: 2 cups flour + 3 eggs + 1 tbs oil → 4 waffles

A)48
B)9
C)12
D)16
E)not enough information

Question 54

Given that 4 NH₃ + 5 O₂ → 4 NO + 6 H₂O,if 3.00 mol NH₃ were made to react with excess of oxygen gas,the amount of H₂O formed would be:

A)2.00 mol.
B)3.00 mol.
C)4.50 mol.
D)6.00 mol.
E)none of the above

Question 55

How many moles of sodium metal are needed to make 3.6 moles of sodium chloride? Given the reaction:
2Na + Cl₂ → 2NaCl

A)0.9
B)7.2
C)1.8
D)3.6
E)not enough information

Question 56

Many metals react with halogens to give metal halides.For example, 2 Al (s)+ 3 Cl₂(g)→ 2 AlCl₃ (s)
If you begin with 13.5 g of aluminum:

A)you will need 23.6 g Cl₂ for complete reaction and will produce 66.7 g of AlCl_3.
B)you will need 53.2 g Cl₂ for complete reaction and will produce 66.7 g of AlCl_3.
C)you will need 26.6 g Cl₂ for complete reaction and will produce 49.0 g of AlCl_3.
D)you will need 11.8 g Cl₂ for complete reaction and will produce 49.0 g of AlCl_3.
E)none of the above

Question 57

How many moles of water are made from complete reaction of 1.4 moles of hydrogen gas? Given the reaction:
2H₂ + O₂ → 2H₂O

A)2.8
B)0.7
C)1.4
D)2.1
E)not enough information

Question 58

Given the balanced equation CH₄ + 2 O₂ → CO₂ + 2 H₂O,which of the following is NOT a correct conversion factor?

A)2 mole H₂O = 18.02 g
B)1 mole O₂ = 32.00 g
C)1 mole CH₄ 2 mole H₂O
D)2 mole O₂ 1 mole CO₂
E)none of the above

Question 59

Iron metal reacts with oxygen to produce iron(III)oxide.If you have 12.0 moles of iron for complete reaction,you need:

A)9.0 moles of O₂ and produce 3.0 moles of Fe₂O₃.
B)12.0 moles of O₂ and produce 24.0 moles of Fe₂O₃.
C)9.0 moles of O₂ and produce 6.0 moles of Fe₂O₃.
D)4.5 moles of O₂ and produce 3.0 moles of Fe₂O₃.
E)none of the above

Question 60

How many moles of H₂ can be made from complete reaction of 3.0 moles of Al? Given:
2 Al + 6 HCl → 2 AlCl₃ + 3 H₂

A)3 moles
B)3.0 moles
C)4.5 moles
D)9.0 moles
E)none of the above

Question 61

Given the balanced equation CO₂ + Si → SiO₂ + C,if you were to react 1 mole of CO₂ with 1 mole of Si,which statement is TRUE?

A)The CO₂ is the limiting reactant.
B)The Si is the limiting reactant.
C)The SiO₂ is the limiting reactant.
D)You have equal stoichiometric amounts of reactants.
E)none of the above

Question 62

Which ingredient is the limiting reactant if you have 6 cups of flour,9 eggs and 2 tbs of oil? Given: 2 cups flour + 3 eggs + 1 tbs oil → 4 waffles

A)flour
B)eggs
C)oil
D)waffles
E)not enough information

Question 63

Which ingredient is the limiting reactant if you have 5 cups of flour,9 eggs and 3 tbs of oil? Given: 2 cups flour + 3 eggs + 1 tbs oil → 4 waffles

A)flour
B)eggs
C)oil
D)waffles
E)not enough information

Question 64

How many grams of NO₂ are theoretically produced if we start with 1.20 moles of S and 9.90 moles of HNO₃?
Reaction: S + 6HNO₃ → H₂SO₄ + 6NO₂ + 2H₂O

A)7.20
B)331
C)455
D)786
E)not enough information

Question 65

What is the theoretical yield of a reaction if 25.0 grams of product were actually produced from a reaction that has a 88% yield?

A)28.4
B)22.0
C)3.52
D)352
E)none of the above

Question 66

A balanced chemical equation used to prepare ammonium carbonate,(NH₄)₂CO₃ ,is:
Which choice of reactant quantities shown below would result in the greatest amount of ammonium carbonate being formed?

A)React 2 moles NH₃ ,1 mole CO₂ ,and 1 mole H₂O
B)React 2 moles NH₃ ,8 moles CO₂ ,and 8 moles H₂O
C)React 4 moles NH₃ ,1 mole CO₂ ,and 2 moles H₂O
D)React 4 moles NH₃ ,2 moles CO₂ ,and 2 moles H₂O
E)none of the above

Question 67

What is the limiting reactant for the following reaction given we have 3.4 moles of Ca(NO₃)₂ and 2.4 moles of Li₃PO₄?
Reaction: 3Ca(NO₃)₂ + 2Li₃PO₄ → 6LiNO₃ + Ca₃(PO₄)₂

A)Ca(NO₃)₂
B)Li₃PO₄
C)LiNO₃
D)Ca₃(PO₄)₂
E)not enough information

Question 68

What is the excess reactant for the following reaction given we have 3.4 moles of Ca(NO₃)₂ and 2.4 moles of Li₃PO₄?
Reaction: 3Ca(NO₃)₂ + 2Li₃PO₄ → 6LiNO₃ + Ca₃(PO₄)₂

A)Ca(NO₃)₂
B)Li₃PO₄
C)LiNO₃
D)Ca₃(PO₄)₂
E)not enough information

Question 69

What is the theoretical yield of waffles if you have 6 cups of flour,9 eggs and 2 tbs of oil? Given: 2 cups flour + 3 eggs + 1 tbs oil → 4 waffles

A)10
B)12
C)8
D)4
E)not enough information

Question 70

What is the theoretical yield of waffles if you have 5 cups of flour,9 eggs and 3 tbs of oil? Given: 2 cups flour + 3 eggs + 1 tbs oil → 4 waffles

A)10
B)12
C)6
D)4
E)not enough information

Question 71

A tricycle factory uses the following items to produce one tricycle: 3 tires,1 frame,and 2 pedals. If the factory has available 270 tires,90 frames,and 170 pedals,which item would limit the amount of complete tricycles that can be assembled?

A)tires
B)frames
C)pedals
D)both tires and frames are limiting
E)not enough information

Question 72

Determine the theoretical yield of C when 3 units of A and 10 units of B are reacted in the following generic chemical equation: 2A + 5B → 4C.

A)3
B)4
C)6
D)8
E)none of the above

Question 73

Which of the following statements is false?

A)The limiting reactant is completely consumed in a chemical reaction.
B)The theoretical yield is the amount of product that can be made based on the amount of limiting reagent.
C)The actual yield is the amount of product actually produced by a chemical reaction.
D)The percent yield = × 100%.
E)All of the above are true statements.

Question 74

Consider the following generic chemical equation: 2A + 5B → C + 3D If you react 4 units of A with 10 units of B,which statement is TRUE?

A)Substance A will be the limiting reactant.
B)Substance B will be the limiting reactant.
C)There is just enough of A and B so that everything reacts completely.
D)Substance C cannot be formed from this reaction.
E)none of the above

Question 75

If the theoretical yield of a reaction is 42.0 grams of product and the percent yield is 75%.How many grams were actually produced?

A)5400
B)56
C)32
D)1.8
E)none of the above

Question 76

Consider the following generic chemical equation: 2W + 3X → 3Y + Z When 5 units of W and 6 units of X are allowed to react,the limiting reactant would be:

A)W
B)X
C)Y
D)Z
E)There is no limiting reactant in this situation.

Question 77

The theoretical yield of a reaction is 75.0 grams of product and the actual yield is 42.0g.What is the percent yield?

A)75.0
B)56.0
C)31.5
D)178
E)none of the above

Question 78

A chemist wishes to perform the following reaction: N₂ + 3 H₂ → 2 NH₃ If only 14.0 g of N₂ is available,what is the minimum amount,in grams,of H₂ needed to completely react with this quantity of N₂?

A)1.01 g
B)1.51 g
C)3.03 g
D)6.06 g
E)none of the above

Question 79

How many grams of calcium phosphate are theoretically produced if we start with 3.40 moles of Ca(NO₃)₂ and 2.40 moles of Li₃PO₄?
Reaction: 3Ca(NO₃)₂ + 2Li₃PO₄ → 6LiNO₃ + Ca₃(PO₄)₂

A)310
B)248
C)1054
D)351
E)not enough information

Question 80

How many moles of lithium nitrate are theoretically produced if we start with 3.4 moles of Ca(NO₃)₂ and 2.4 moles of Li₃PO₄?
Reaction: 3Ca(NO₃)₂ + 2Li₃PO₄ → 6LiNO₃ + Ca₃(PO₄)₂

A)7.2
B)6.8
C)1.2
D)1.1
E)not enough information