OSSLT Practice and Chemistry Review
For each of the three sections, read the selected passage and answer the questions that follow.
Please Pass the Salt!
Acids are substances that react with metals and carbonates, conduct electricity, turn blue litmus red, and taste sour. Bases, on the other
hand, are substances that conduct electricity, feel slippery, and taste bitter. The lack of acidity in a substance makes it more basic and
vice versa. The acidity of a substance is measured by a scale called the pH scale, which is shown below. The pH scale assigns numbers
from 0 to 14 to substances based on the acidity of the substance, where 0 is very acidic and 14 is very basic. Pure water is the perfect
balance of acidity and is neutral.
Acids and bases work to neutralize each other. For example, a bee sting contains an acid that causes pain in the area of the sting. By
covering the sting with a paste made from baking soda, which is a basic substance, it helps to neutralize the acid and bring comfort to
the person.
When an acid and a base are mixed, they form a salt. A salt is composed of the positive base ion and the negative acid ion. For example,
table salt is formed from the positive sodium ion, Na+, combined with the negative chlorine ion, Cl-, forming NaCl. There are also families
of salts. Chlorides all have hydrochloric acid as their acid part. Sulfates all have sulfuric acid as their acid part. There are many families
and types of salt as the substances combined vary.
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What does the pH scale measure?
a. the amount of base in the substance
b. the acidity of a substance
c. the chemical composition of the substance
d. the quantity of a substance
What is the purpose of the phrase “on the other hand” in paragraph 1?
a. to transition to a new idea
b. to conclude an idea
c. to contrast ideas
d. to introduce a new idea
Which of the following would acids and bases be considered when comparing them?
a. the same
b. chemically similar
c. neutral substances
d. opposites
Which of the following determines the type of family a salt belongs to?
a. taste
b. practical uses
c. original substances
d. type of salt it produces
The pH of milk makes it
a. more acidic
b. more basic
c. neutral
d. none of the above
What do salts have to do with acids and bases?
a. Salt is an acid.
b. Salt is a base.
c. Salt is a mixture of an acid and a base.
d. They are unrelated
How do acids and bases affect each other?
a. ferment
b. neutralize
c. explode
d. acid “eats” the base
Which of the following words could replace “vice versa” in paragraph 1?
a. reversibly
b. conversely
c. oppositely
d. contrarily
The Law of Conservation of Mass
In science, a law is a fundamental principle that has been proven to always be true under the same conditions. The law of conservation
of mass states that in any given chemical reaction, the total mass of the reactants equals the total mass of the products. In other words,
the amount of mass of any elements involved before any chemical reaction is equal to the amount of mass of the resulting elements after
the reaction. There are no fewer particles after the reaction than there were before the reaction. Mass cannot be created or destroyed.
During a chemical reaction, the form the particles are in may change. For example, when a pile of wood is burned in a fire, the mass is
transformed from wood to smoke, gases, ash, and wood remnants.
This law enables chemists to represent all chemical reactions using equations. Since the mass is equal before and after the chemical
reaction, the equation will balance and each side will represent the same mass. Another consequence of the law is that the types of
atoms will not change during the reaction. If the mass involved in the reaction is composed of carbon and oxygen atoms, the resulting
mass will also consist of carbon and oxygen atoms after the reaction. The atoms may be rearranged into new forms, but they will be the
same atoms involved. So, for the equation to balance, the types and number of atoms must match before and after the reaction.
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The law of conservation of mass says that
a. Mass can be destroyed.
b. Mass can be created.
c. Mass can be neither created nor destroyed.
d. Mass transfers to energy.
In the law being discussed in the selection, what is another word that could be used for “conservation”?
a. management
b. preservation
c. creation
d. destruction
How can visually apparent mass that is present before and not after a chemical reaction be accounted for?
a. It was destroyed.
b. It was removed.
c. It was transformed to other forms that are not visible.
d. This cannot happen.
How often is a scientific law true?
a. always
b. sometimes
c. never
d. It depends on the law.
What is the meaning of the word “consequence” in paragraph 3?
a. punishment
b. importance
c. cause
d. result
What is the purpose for the words “In other words” in paragraph 1?
a. to provide a new definition
b. to transition to a new idea
c. to offer a simpler explanation
d. to support a stated fact
What is true about an equation representing a chemical reaction?
a. The number of atoms on each side of the equation will be the same.
b. The types of atoms on each side of the equation will be the same.
c. The total mass represented on each side of the equation will be the same.
d. all of the above
If the original mass consists of 3 atoms of hydrogen and 2 atoms of oxygen, which of the following could be the result after a
chemical reaction?
a. (2 hydrogen and 2 oxygen) + (1 hydrogen and 1 oxygen)
b. (2 hydrogen and 1 oxygen) + (1 hydrogen and 1 oxygen)
c. (1 hydrogen and 1 oxygen) + (1 hydrogen and 2 oxygen)
d. (2 hydrogen and 1 oxygen)
The Periodic Table
Dmitri Mendeleev was a famous Russian scientist who invented the periodic table as a way to classify and explain all of the known
elements during his time. At the time, there were 65 known elements. Mendeleev brilliantly left gaps in his table to account for yet
undiscovered elements. This differentiated his table from others that were already created. As of July, 2009, there were 117 elements in
the standard table.
Usually, the periodic table lists each element with its elemental symbol and atomic number. The atomic number is the number of protons
in the nucleus of the element. The elements of the periodic table are arranged in order of increasing atomic number.
The elements of the periodic table can be classified as metals, non-metals, and metalloids. The table usually distinguishes these
classifications by using color. Hydrogen is the exception and is really in a group of its own. The periodic table also categorizes elements
into periods and groups. Each row of elements on the periodic table is called a period. Each column is a group of elements with similar
chemical properties. Most of the known elements are metals. Metals are solid, shiny, generally malleable, and good conductors of heat
and electricity. The non-metals can be in solid, liquid, or gas form. They are dull and brittle, and are insulators. Metalloids represent the
few elements that are semi-metals, elements between metals and non-metals. The characteristics of metalloids fall in between the
characteristics of metals and non-metals and can vary by element.
17. What separated the periodic table that Mendeleev invented from others that were created?
a. His was more comprehensive for the time.
b. He discovered more elements than all of the others.
c. His was organized better.
d. He left gaps for undiscovered elements.
18. What does the word “differentiated” mean in the first paragraph?
a. distinguished
b. elevated
c. suppressed
d. dignified
19. Why is the date important in paragraph 1?
a. The paragraph is about history and dates are important.
b. There may be more elements discovered in the future.
c. An important event happened on that date.
d. It was when the periodic table was invented.
20. How would scientists identify elements that are yet to be discovered?
a. by chance
b. missing elements by period in the periodic table
c. missing atomic numbers in the sequence of the periodic table
d. missing elements by group in the periodic table
21. What is the purpose of the words “elements between metals and non-metals” in paragraph 3?
a. to provide clarification
b. to support a fact
c. to define a word
d. to introduce a transition
22. Most of the known elements are
a. metals
b. metalloids
c. non-metals
d. gases
23. How are the atomic numbers of elements utilized on the periodic table?
a. only way to identify the element on the table
b. group the elements in sequence in decreasing order
c. group the elements in sequence in increasing order
d. not utilized
24. How are different classifications of elements usually distinguished on the periodic table?
a. by color
b. by element symbol
c. by atomic number
d. by groups