Download Kitchen Chemistry Review

Kitchen Chemistry Review
Chemical Reactions, Role of Baking Ingredients, Biochemicals, Acids and Bases
Chemical Reactions
Be able to recognize if a change is physical or
chemical, giving reasons why.
Physical: Change in shape, size, state or amount
Chemical: Change in chemical composition, new
substance is made.
Physical and Chemical Changes
https://www.quia.com/quiz/303980.html
Parts of an Equation
Practice Questions
1. A substance that enters into a chemical
reaction is called a
a. mole.
c. coefficient.
b. product.
d. reactant.
Answer: D
Practice Questions
In a reaction in which hydrogen reacts with
oxygen to produce water, which substances are
the reactants?
a. hydrogen only c. both hydrogen and oxygen
b. oxygen only
Answer: C
d. water
Practice Questions
In a chemical equation, the symbol that takes the
place of the word yields is a(n)
a. equal sign.
c. plus sign.
b. coefficient.
d. arrow.
Practice Questions
When oxygen is available, sulfur dioxide is produced from
the burning of sulfur. Which of the following word
equations best represents this reaction?
a. sulfur + oxygen => sulfur dioxide
b. sulfur dioxide + oxygen =>sulfur
c. sulfur dioxide = >sulfur + oxygen
d. sulfur => sulfur dioxide + oxygen
Answer: A
Practice Questions
The word equation “magnesium reacts with chlorine to
produce magnesium chloride” would be represented
by which of the following formula equations?
a. Mg => Cl2 + MgCl2
b. MgCl2 => Mg+ Cl2
c. MgCl2 + Mg => Cl2
d. Mg + Cl2 =>MgCl2
Answer: D
Practice Questions
The symbol (s) written after a formula in a
chemical equation stands for
a. soluble.
c. solid.
b. solution.
d. synthesis.
Answer: C
Practice Questions
Which of the following symbols means a
substance is in water solution?
a. (aq)
c. (w)
b. (s)
d. (l)
Answer: A
Be able to identify the 5 types of chemical
reactions
Synthesis: A + B=> AB
Decomposition: AB => A + B
Combustion: Chemical + oxygen → carbon dioxide + water
Single Displacement (Replacement) A + BC => AB + C
Double Displacement (Replacement) AB + CD => AC + BD
Practice Questions
What kind of reaction is represented by the equation
C2Cl4 + Cl2 => C2Cl6?
a. synthesis
c. single replacement
b. double replacement
d. combustion
Answer: A
Practice Questions
The reaction 2Mg(s) + O2(g) <= 2MgO(s) is a
a. synthesis reaction. c. single-replacement reaction.
b. decomposition reaction. d. double-replacement
reaction.
Answer: B
Practice Questions
The reaction Mg(s) + 2HCl(aq) =>H2(g) + MgCl2(aq) is a
a. composition reaction.
c. single-replacement reaction.
b. decomposition reaction.
d. double-replacement
Answer: C
Practice Questions
The reaction Pb(NO3)2(aq) + 2KI(aq) => PbI2(s) +
2KNO3(aq) is a
a. double-replacement reaction. c. decomposition
reaction.
b. synthesis reaction.
Answer: A
d. combustion reaction.
Law of Conservation of Mass (Matter)
Atoms can be neither created nor destroyed in a
chemical reaction.
Number of atoms on reactant side = Number on
product side
Mass stays the same
Practice Questions
To balance a chemical equation, it may be
necessary to adjust the
a. coefficients.
c. formulas of the products.
b. subscripts.
d. number of products.
Answer: A
Practice Questions
According to the law of conservation of mass, the total mass of
the reacting substances is
a. always more than the total mass of the products.
b. always less than the total mass of the products.
c. sometimes more and sometimes less than the total mass of
the products.
d. always equal to the total mass of the products.
Answer: D
Practice Questions
P + O2 → P4O10
Is this equation balanced? Yes / No
Answer : No
Practice Questions
4 Fe + 3O2 → 2 Fe2O3
Fe =
Fe =
 O=
O=
Is this equation balanced? Yes / No
Answer: Yes
Practice Questions

2(NH4)2+Cr2O7
How many of each element are there?
Answer:
4N
16H
2Cr
7O
Baking Ingredients
Be able to identify the role of baking ingredients:
Sugar – tenderizer, adds moistness, causes browning
Salt – Adds flavor, Controls reaction of yeast
Leavening Agents: Produce CO2, pushing dough or
batter up as the gas tries to escape
Egg whites – serves as leavening agent as air is
whipped into whites
Baking Ingredients
Egg Yolks – add flavor and tenderness
Milk – Add nutrients, helps objects brown, activates
reactions as a liquid
Flour – binds ingredients together, protein (gluten) is
developed with stirring, More protein – chewier product
is
Practice Questions
What baking ingredient is responsible for browning of
baked goods?
A. Salt
B. Sugar
Answer: B
C. Flour
D. Leavening Agent
Practice Questions
Which of the following is NOT a leavening agent?
A. Baking Soda
D. Cream of Tartar
Answer: D
B. Baking Powder
C. Egg Whites
Practice Questions
 You are baking muffins. When it comes out of the oven, you notice that
there are lots of holes in the muffins. What might have happened?
A. Too much leavening agent was added
B. It was cooked at too hot of a temperature
C. Too much sugar was added
D. Too much fat was added
Answer: A
Practice Questions
 If cooking loaf bread, what type of flour would be best?
A. One with a high amount of protein
B. One with a small amount of protein
C. One with no protein
D. It doesn’t matter
Answer: A
Practice Questions
 Your cookies have coagulated. What has happened?
 A. They have turned brown
 B. The sugar has melted and is syrup-lik
 C. The water has escaped, turning the batter into a solid
Answer: C
Practice Questions
 I am making pancakes. I am going to use artificial sugar instead of
regular sugar. My pancakes are light and fluffy, but they never turned
brown. What happened?
 A. You work cooking at too low of a temperature
 B. You did not have sugar which helps it brown
 C. You used the wrong type of flour
 D. You didn’t put in enough artificial sugar.
 Answer: B
Practice Questions
 Why does the cake on the right have larger holes than the cake of the
left?
 A. The cooking temperature was too high.
 B. There was too much salt
 C. The leavening agent was producing more gas
 D. All are correct
 Answer: C
Practice Questions
 What chemical processes have happened in this picture?
 A. Fermentation
B. Coagulation
 C. Denaturation
D. All of above
 Answer: B, C
Practice Questions
 What happened to my yeast bread in this picture?
 A. It did not have enough flour
 B. It did not have any fats
 C. It did not have salt, so it reacted too quickly.
 D. There was no egg whites.
 Answer: C
Practice Questions
 My cookies turned out terrible. They never turned brown. They are tough
and dry. What mistakes did I make?
 Answer:
 Not enough sugar
 Perhaps the heat was too low to brown
 You overmixed the dough developing too much gluten
 Answer: All are correct
Leavening Agents
 Baking Soda – Needs acid to react to produce carbon dioxide
 Baking Powder – Made of baking soda, thickener, and added acids.
Single acting – reacts when mixed with liquid to produce CO2
Double acting – two acids, reacts with mixed and when heat is added
Cream of tartar – acid that is added to baking powder
 Steam – produces steam which rises and helps bring up dough or batter
 Egg whites – whipped to incorporate air which helps batter to rise
 Yeast – biological agent that makes carbon dioxide when fed sugar,
needs warm temperatures
Practice Question
 I am making pancakes with baking soda and regular milk. They do not
get light and fluffy. What was missing?
 A. Leavening Agent
B. Acid
 C. Eggs
D. Flour
 Answer: B
Practice Question
 Which of the following are acids added to baking powder?
 A. Cream of tartar
 B. Lemon juice
 C. All Purpose flour
 D. Vinegar
 Answer: A
Practice Question
 I am making yeast bread. My bread does not rise. What might have
been the problem?
 A. You may not have added sugar
 B. You may have not mixed it enough
 C. You may have used cold liquids
 D. All of the above
 Answer D
Practice Questions
 My muffins turned out tough and too chewy. I used all purpose flour.
What did I do wrong?
 Answer: You might have overstirred, developing gluten too much
Practice Questions
 Which flour would be more suitable for making cinnamon rolls?
 A. Cake flour
 B. All purpose flour
 C. Bread flour
 Answer: B – want it to be more tender
Biochemicals
 Carbohydrates:
Building block – monosaccharides
Elements: Carbon, Hydrogen, Oxygen
Functions: provide energy
Foods: Fruits, Vegetables, Sweet products such as cake, cookies, etc…
Biochemicals
 Lipids:
Building blocks: Glycerol and Fatty Acids
Elements: Carbon, Hydrogen, Oxygen
Functions: Long-term energy storage, make up the cell membranes
(phospholipids), hormones
Foods: Fats and Oils, Cholesterol, Waxes
Fats – saturated (solid)
Oils – unsaturated (liquid)
Biochemicals
 Proteins:
 Building Block: Amino Acids (20)
 Elements: Carbon, hydrogen, oxygen, nitrogen, sometimes sulfur
 Functions: enzymes, cell membrane, provide structure, building
materials, hormones
 Foods: Meats, Eggs, Nuts, Legumes (beans and peas), Dairy products
Biochemicals
 Nucleic Acids
 Building Blocks: Nucleotides
 Functions: Genetic makeup (DNA), protein synthesis (RNA)
 Foods: All food from living things
Other nutrients:
 Vitamins – organic molecules helps with chemical reactions in body,
growth and metabolism
 Minerals – inorganic molecules that also help with chemical reactions,
building materials
 Water – activates chemical reactions, helps transport nutrients through
blood
 Organic – contains Carbon
 Inorganic – does not contain Carbon
Practice Questions:
 Which is the primary biomolecule that is found in eggs?
 Answer: Protein
Practice Questions
 What would fruits be classified as:
 A. Carbohydrates
 C. Proteins
 Answer: Carbohydrates
B. Lipids
Practice Questions
 What would DNA be classified as:
 A. Carbohydrates
B. Lipids
 C. Proteins
D. Nucleic Acids
 Answer: Nucleic Acids
Practice Questions
 What are these food items classified as:
 A. Carbohydrates
 C. Proteins
 Answer: Lipids
B. Lipids
Practice Questions
 What are these food items classified as:
 A. Carbohydrates
 C. Proteins
 Answer: Proteins
B. Lipids
Practice Questions
 What 2 biochemicals have the same elements?
 A. Carbohydrates
B. Lipids
 C. Proteins
D. Nucleic Acids
 Answer: A and B
Practice Questions
 What biochemicals are in your cell membranes?
 A. Protein
 C. Lipids
 Answer: A and C
B. Carbohydrates
Practice Questions
 What biochemical gives you instant energy?
 A. Protein
 C. Lipids
 Answer: B
B. Carbohydrates
Acids and Bases
 Acids: Sour Taste, release H+ ions when dissolved in water, pH 0 – 6.99
 Bases: Bitter Taste, release OH-, pH 7.001 to 14
 Closer an acid or base is to 7, weaker
 Further away from 7, stronger
 7 is neutral
Acids and Bases
Body uses acids in digestive system, makeup of many vitamins
Body uses bases to help neutralize acids
Kidney and lungs help get rid of excess acids and bases
Kidneys produce bicarbonates (bases)
Lungs carry out acids with exhaling of carbon dioxide
Blood’s pH should be 7.4
Practice Questions
What object is a stronger acids?
A. Soda
B. Milk
C. Apple
D. Shampoo
Answer: A
Practice Questions
What object is a stronger Base?
A. pH of 14
B. pH of 2
C. pH of 7
D. pH of 8
Answer: A
Practice Questions
What object is an acid?
A. pH of 14
B. pH of 2
C. pH of 7
D. pH of 8
Answer: A
Practice Questions
What is another name for alkalines:
A. Acids
Answer: B
B. Bases
C. Neutral compounds
Practice Questions
What is blood?
A. Acid
B. Base
Answer: B (7.4 pH)
C. Neutral
Practice Questions
Of the pictured items, which is a stronger acid?
Answer: Vinegar