1.
Which of the following elements will form positive ions by losing electrons during bonding
Correct Answer
C. Calcium (Ca)
Explanation
Calcium (Ca) will form positive ions by losing electrons during bonding because it has two valence electrons in its outermost energy level. To achieve a stable electron configuration, calcium can easily lose these two electrons and form a +2 ion. This results in a full outer energy level, similar to the noble gas configuration of argon. Sulfur (S), Neon (Ne), and Fluorine (F) are unlikely to lose electrons during bonding as they have a stable electron configuration already.
2.
The group of elements on the periodic table are most likely to make negative ions by “gaining” valence electrons?
Correct Answer
A. Nonmetals.
Explanation
Nonmetals are the elements that are most likely to make negative ions by "gaining" valence electrons. This is because nonmetals have a higher electronegativity, which means they have a stronger attraction for electrons. When nonmetals react with other elements, they tend to gain electrons to achieve a stable electron configuration, forming negative ions. Metals, on the other hand, are more likely to lose valence electrons and form positive ions. Metalloids have properties that are intermediate between metals and nonmetals, but they are not as likely to gain electrons as nonmetals. Noble gases are already stable with a full valence shell, so they do not readily gain or lose electrons.
3.
What is the common ion charge for the element oxygen (O?)?
Correct Answer
E. 2-
Explanation
The common ion charge for the element oxygen (O) is 2-. This means that oxygen typically gains 2 electrons when it forms an ion.
4.
What is the common ion charge for the element aluminum (Al)?
Correct Answer
A. 3+
Explanation
The common ion charge for the element aluminum (Al) is 3+. This means that when aluminum forms an ion, it tends to lose three electrons, resulting in a positive charge of 3+.
5.
The ion calcium (Ca2+) and the ion Chlorine (Cl1-) form a compound with the formula: A) CaCl B) Ca2Cl C) CaCl2 D) Cl2Ca E) Ca2Cl2
Correct Answer
C. C
Explanation
The correct answer is C) CaCl2. This is because the compound formed between calcium (Ca2+) and chlorine (Cl1-) requires two chloride ions to balance the charge of one calcium ion. Therefore, the correct formula is CaCl2.
6.
Which of these ions is a polyatomic ion?A) Ca2+ B) OH1- C) Mg2+ D) Br1-
Correct Answer
B. OH1-
Explanation
OH1- is a polyatomic ion because it consists of two or more atoms that are covalently bonded and carry a net electric charge. In this case, OH1- is composed of one oxygen atom and one hydrogen atom, bonded together and carrying a charge of -1.
7.
What is the net electrical charge for all chemical compounds?
Correct Answer
C. Neutral
Explanation
Chemical compounds consist of atoms that can either gain or lose electrons. When atoms gain or lose electrons, they become charged particles called ions. In a chemical compound, the positive charges of the cations (positively charged ions) balance out the negative charges of the anions (negatively charged ions), resulting in a net charge of zero. Therefore, the net electrical charge for all chemical compounds is neutral.
8.
. What is the chemical name for the ionic compound with the chemical formula: LiBr?
Correct Answer
C. Lithium Bromide
Explanation
Lithium bromide is the correct answer because the chemical formula LiBr represents an ionic compound composed of lithium cations (Li+) and bromide anions (Br-). The naming convention for ionic compounds involves using the name of the cation followed by the name of the anion, so in this case, "Lithium" represents the cation and "Bromide" represents the anion.
9.
. Using the chart below for polyatomic ions write the formula for the compound made between the element calcium and the polyatomic ion sulfate. a) Ca(SO4)2 b) CaSO42 C) Ca2(SO4)2 d) CaSO4
Correct Answer
D. D
Explanation
The formula for the compound made between calcium and the sulfate ion is CaSO4. This is because the sulfate ion has a charge of -2 and calcium has a charge of +2. In order to balance the charges, one calcium ion is needed to combine with one sulfate ion, resulting in the formula CaSO4.
10.
To form an ionic bond the ions are formed when the valence electron(s) is/ are ____
Correct Answer
A. SHARED
Explanation
Ionic bonds are formed when one or more valence electrons are transferred from one atom to another, resulting in the formation of positively charged cations and negatively charged anions. Therefore, the correct answer is "TRANSFERRED".
11.
Magnesium becomes a 2+ ion by __________.
Correct Answer
A. losing 2 valence electrons.
Explanation
Magnesium becomes a 2+ ion by losing 2 valence electrons. When magnesium loses these electrons, it achieves a stable electron configuration similar to that of a noble gas, which is energetically favorable. This loss of electrons results in a positive charge of 2+, as the number of protons in the nucleus remains the same while the number of electrons decreases.
12.
Which of the following is the correct formula for copper sulfate?
(Copper ion has a 2+ charge and sulfate is a polyatomic ion) A) CuSO4 B) CuSO3 C) Cu(SO4)2 D) Cu(SO3)2
Correct Answer
A. A
Explanation
The correct formula for copper sulfate is CuSO4. Copper ion has a 2+ charge and sulfate is a polyatomic ion with a 2- charge. To balance the charges, one copper ion combines with one sulfate ion, resulting in CuSO4.
13.
An element “X” bonds with sulfur to form a neutral ionic compound with the formula X2S3. What is the ion charge of the element “X”?
Correct Answer
C. 3+
Explanation
The ion charge of the element "X" is 3+ because the formula of the compound is X2S3. In this formula, the subscript 2 indicates that there are two X ions, and the subscript 3 indicates that there are three S ions. Since the compound is neutral, the total positive charge of the X ions must balance out the total negative charge of the S ions. Therefore, each X ion must have a charge of 3+ in order to balance out the 3- charge of the S ions.
14.
For a neutral atom to become an ion it will lose or gain
Correct Answer
C. Electrons
Explanation
When a neutral atom becomes an ion, it either loses or gains electrons. Electrons are negatively charged particles that orbit the nucleus of an atom. By gaining or losing electrons, the atom's overall charge changes, resulting in the formation of an ion. Losing electrons makes the atom positively charged, while gaining electrons makes it negatively charged. Neutrons and protons are found in the nucleus of an atom and do not directly affect its charge when gained or lost. Nucleons is a term that refers to both protons and neutrons collectively.
15.
Ionic bonds form when…
a) two atoms come close enough to begin sharing electrons. b) two atoms begin attracting each other electrons. c) an electron transfer creates two oppositely charged ions. d) all the above are true.
Correct Answer
C. an electron transfer creates two oppositely charged ions.
Explanation
Ionic bonds form when an electron transfer creates two oppositely charged ions. In an ionic bond, one atom donates electrons to another atom, resulting in the formation of positively charged cations and negatively charged anions. These oppositely charged ions are then attracted to each other, forming a strong bond. The other options mentioned, such as atoms sharing electrons or attracting each other's electrons, do not accurately describe the process of forming an ionic bond.
16.
.  Which of the following elements is LEAST likely to become an ion?
     
Correct Answer
D. Ne
Explanation
Neon (Ne) is least likely to become an ion because it is a noble gas. Noble gases have a stable electron configuration with a full outer shell, making them highly unreactive and unlikely to gain or lose electrons to form ions. In contrast, elements like calcium (Ca), oxygen (O), and aluminum (Al) are more likely to become ions because they can gain or lose electrons to achieve a stable electron configuration.
17.
. Which of the following pairs of elements will make an ionic bond?
               
Correct Answer
B. Sr and I
Explanation
Sr and I will make an ionic bond because Sr is a metal and I is a non-metal. In an ionic bond, electrons are transferred from the metal to the non-metal, creating positive and negative ions. Sr will lose two electrons to become Sr2+ ion, while I will gain one electron to become I- ion. The attraction between the positive and negative ions will form the ionic bond.
18.
A covalent bond forms when …
Correct Answer
A. two atoms are each trying to take each other’s electrons while holding onto their own electrons
Explanation
In a covalent bond, two atoms share electrons in order to fill their outermost electron shells. This allows both atoms to achieve a more stable electron configuration. In this explanation, it is stated that two atoms are each trying to take each other's electrons while holding onto their own electrons. This implies that both atoms are actively participating in the sharing of electrons, rather than one atom transferring electrons to the other.
19.
When chemists write chemical formulas for compounds, which ion is written first in the compound’s chemical formula?
Correct Answer
D. Positive ion
Explanation
In chemical formulas for compounds, the positive ion is written first. This is because the positive ion, also known as the cation, is usually a metal or a positively charged polyatomic ion. The cation is typically the element or group that loses electrons and forms a positive charge. On the other hand, the negative ion, or anion, is usually a nonmetal or a negatively charged polyatomic ion. The anion is the element or group that gains electrons and forms a negative charge. By convention, the positive ion is always written first in chemical formulas to indicate its presence in the compound.
20.
Which of these pairs of elements is most likely to make a covalent bond?
Correct Answer
D. H and O
Explanation
H and O are most likely to make a covalent bond because they are both nonmetals. Covalent bonds occur between nonmetals by sharing electrons, rather than transferring them as in ionic bonds. H and O are both nonmetals and have a relatively small difference in electronegativity, making them more likely to share electrons and form a covalent bond.
21.
Which of the following does not indicate a chemical change has occurred?
Correct Answer
C. Change in surface area
Explanation
A change in surface area does not indicate a chemical change because it is a physical change. Chemical changes involve the rearrangement of atoms and the formation of new substances with different properties. In contrast, a change in surface area only affects the physical appearance of a substance, such as breaking a solid into smaller pieces or grinding it into a powder. The chemical composition of the substance remains the same, so it is not a chemical change.
22.
. When balancing equation, you are only allowed to change the _________ in the chemical equation.
Correct Answer
C. Coefficients
Explanation
When balancing an equation, you are only allowed to change the coefficients in the chemical equation. The coefficients represent the number of molecules or atoms involved in the reaction, and by adjusting them, you can ensure that the number of atoms on both sides of the equation is equal. Changing the subscripts would alter the chemical formula and therefore the identity of the substances involved, while changing the reactants or products would completely change the nature of the reaction.
23.
Which of the following equation is chemically balanced?
a) 2H2O à H2 + O2b) Zn + 2HCl à ZnCl2 + H2c) C2H5OH + 2O2 à 3CO2 + 3H2Od) NaOH + 2HCl à NaCl + H2O
Correct Answer
B. B
Explanation
The equation in option b) Zn + 2HCl à ZnCl2 + H2 is chemically balanced because the number of atoms of each element is the same on both sides of the equation. There are 1 zinc atom, 2 hydrogen atoms, and 1 chlorine atom on both sides of the equation. Additionally, the charges are also balanced, as there are no charges present in the equation.
24.
The burning of wood is an example of a ____________ reaction.
Correct Answer
A. Exothermic
Explanation
The burning of wood releases heat and energy, which is characteristic of an exothermic reaction. In an exothermic reaction, energy is released from the system into the surroundings, resulting in an increase in temperature.
25.
The reaction graph below represents a ________ reaction.
Correct Answer
B. Exothermic
Explanation
The reaction graph shows a decrease in energy as the reaction progresses, indicating that energy is being released. This is characteristic of an exothermic reaction, where the reactants have more energy than the products.
26.
In the Potential Energy in a Chemical Reaction graph above, it can be observed that ________ have more potential energy.
Correct Answer
A. The reactants
Explanation
In the Potential Energy in a Chemical Reaction graph, the reactants have more potential energy. This can be inferred from the graph as the potential energy level is higher for the reactants compared to the products. This indicates that more energy is required to break the bonds in the reactants and initiate the chemical reaction.
27.
When chemical bonds are broken and new substances are created a chemist states ______ has occurred.
Correct Answer
B. A chemical reaction
Explanation
When chemical bonds are broken and new substances are created, a chemist states that a chemical reaction has occurred. This is because a chemical reaction involves the breaking and forming of chemical bonds, resulting in the creation of new substances with different properties. A nuclear reaction, on the other hand, involves changes in the nucleus of an atom and is not related to the breaking and forming of chemical bonds. "No change has occurred" and "mass destruction" are not accurate descriptions of the process of a chemical reaction.
28.
Study the chemical equation below. Identify the chemical products and reactants.
Mg + HCl à MgCl2 + H2
a) Reactants = Mg and Cl, Products = MgCl2 and H2
b) Reactants = Mg and HCl, Products = MgCl2 and H2
c) Reactants = MgCl2 and H2, Products = Mg and HCl
d) Reactants = MgCl and H2, Products = MgCl2 and HCl
Correct Answer
B. B
Explanation
The correct answer is b) Reactants = Mg and HCl, Products = MgCl2 and H2. In the given chemical equation, Mg (Magnesium) and HCl (Hydrochloric acid) are the reactants, as they are the substances that undergo a chemical reaction. The arrow indicates the direction of the reaction, and the products of the reaction are MgCl2 (Magnesium chloride) and H2 (Hydrogen gas). Therefore, option b) correctly identifies the reactants and products in the chemical equation.
29.
In the diagram below is the chemical reaction balanced?
            
Correct Answer
A. Yes
Explanation
The explanation for the correct answer "yes" is that in a balanced chemical reaction, the number of atoms of each element on both sides of the equation is equal. However, since there is no diagram provided, it is impossible to determine if the chemical reaction is balanced or not. Therefore, the explanation for the correct answer is not available.
30.
In this chemical formula for aluminum Sulfate, 4Al2(SO4)3, how many atoms of each element are indicated by the formula?
Correct Answer
B. 8 aluminum, 12 sulfur, and 48 oxygen atoms
Explanation
The chemical formula for aluminum sulfate, 4Al2(SO4)3, indicates that there are 4 molecules of aluminum sulfate. Each molecule of aluminum sulfate contains 2 atoms of aluminum, so multiplying by 4 gives a total of 8 aluminum atoms. Each molecule also contains 3 molecules of sulfate, which consists of 1 sulfur atom and 4 oxygen atoms. Multiplying by 4 gives a total of 12 sulfur atoms and 48 oxygen atoms. Therefore, the correct answer is 8 aluminum, 12 sulfur, and 48 oxygen atoms.
31.
. In the formula for 6 molecules of sodium sulfate, 6Na2SO4, what is the subscript for the sulfur atom?
Correct Answer
C. 1
Explanation
The subscript for the sulfur atom in the formula for 6 molecules of sodium sulfate, 6Na2SO4, is 1. This means that there is only 1 sulfur atom present in each molecule of sodium sulfate.
32.
Which of the following actions would probably speed up the chemical reaction between magnesium and hydrochloric acid?
Correct Answer
D. Breaking the magnesium into smaller pieced or powdering it.
Explanation
Breaking the magnesium into smaller pieces or powdering it would increase the surface area of the magnesium, allowing for more effective collisions between the magnesium and hydrochloric acid molecules. This increased surface area would lead to a higher frequency of successful collisions, resulting in a faster chemical reaction.
33.
Which of the following will increase the chance of extinguishing the combustion of wood?
Correct Answer
B. Lowering the temperature of the fuel.
Explanation
Lowering the temperature of the fuel will increase the chance of extinguishing the combustion of wood because fire requires a certain temperature to sustain itself. By reducing the temperature, the fuel will not reach the necessary heat level to continue burning, thus extinguishing the fire.
34.
Which of the following equation is a synthesis reaction?
a) 2H2O à 2H2 + O2
b) 2Ca + 02 à 2CaO
c) Mg + 2HCl à MgCl2 + H2
d) NaOH + HCl à NaCl + H2O
Correct Answer
B. B
Explanation
In a synthesis reaction, two or more substances combine to form a single, more complex substance. Option b) 2Ca + O2 à 2CaO represents a synthesis reaction because calcium (Ca) and oxygen (O2) combine to form calcium oxide (CaO), which is a single, more complex substance.
35.
. Which of these equations is a double replacement reaction?
a) 2H2O à 2H2 + O2
b) 2Ca + 02 à 2CaO
c) Mg + 2HCl à MgCl2 + H2
d) 2NaOH + MgCl2 à 2NaCl + Mg(OH)2
Correct Answer
D. D
Explanation
The correct answer is d) 2NaOH + MgCl2 → 2NaCl + Mg(OH)2. This equation is a double replacement reaction because the positive and negative ions of two compounds (NaOH and MgCl2) switch places to form two new compounds (NaCl and Mg(OH)2).
36.
The chemical reaction that is the opposite of a synthesis reaction is the…
Correct Answer
B. Decomposition
Explanation
A synthesis reaction is a chemical reaction where two or more substances combine to form a more complex substance. The opposite of this would be a decomposition reaction, where a complex substance breaks down into simpler substances. Therefore, decomposition is the correct answer.
37.
Chemical equation must be balanced to obey the
a) octet rule. b) conservation of mass. c) conservation of energy. d) law of reactions.
Correct Answer
B. Conservation of mass
Explanation
Chemical equations must be balanced to obey the conservation of mass. This means that the total mass of the reactants must be equal to the total mass of the products. Balancing the equation ensures that the same number of each type of atom is present on both sides of the equation, maintaining the principle of mass conservation. The octet rule refers to the arrangement of electrons in an atom's outer shell, not the balancing of chemical equations. Conservation of energy and the law of reactions are not directly related to balancing chemical equations.
38.
Which of these equations is NOT balanced?
a) SO3 à S + O2b) 2H2O à 2H2 + O2c) MnO4 à Mn + 2O2d) 2Cu + O2 à 2CuO
Correct Answer
A. A
Explanation
The equation "SO3 à S + O2" is not balanced because there is only one sulfur atom on the left side of the equation and two sulfur atoms on the right side. In a balanced equation, the number of atoms of each element on both sides of the equation should be equal.
39.
Which of the following is a single replacement reaction?
a) 2H2O à 2H2 + O2
b) 2Ca + 02 à 2CaO
c) Mg + 2HCl à MgCl2 + H2
d) 2NaOH + MgCl2 à 2NaCl + Mg(OH)2
Correct Answer
C. C
Explanation
In a single replacement reaction, one element replaces another element in a compound. In option c, magnesium (Mg) replaces hydrogen (H) in hydrochloric acid (HCl) to form magnesium chloride (MgCl2) and hydrogen gas (H2). This fits the definition of a single replacement reaction. Options a, b, and d do not involve one element replacing another element in a compound.
40.
A logical interpretation based on observation or prior knowledge is called
Correct Answer
B. An inference.
Explanation
An inference is a logical interpretation based on observation or prior knowledge. It involves drawing conclusions or making predictions based on the available evidence. This process allows individuals to make educated guesses or hypotheses about a particular situation or phenomenon. Inferences are important in various fields such as science, literature, and everyday life as they help in understanding and explaining the world around us.
41.
The scientific skill in which you use your senses to gather information is
Correct Answer
C. Observing.
Explanation
Observing is the correct answer because it refers to the scientific skill of using our senses to gather information. When we observe, we carefully watch, listen, and take note of the details or data that we can perceive through our senses. This skill is essential in scientific investigations as it allows us to gather evidence and information that can be used to make further observations, draw conclusions, and develop hypotheses.
42.
A statement that is tested through scientific experiments is called a
Correct Answer
D. Hypothesis.
Explanation
A hypothesis is a statement that is tested through scientific experiments. It is an educated guess or a proposed explanation for a phenomenon or observed data. Through experiments and observations, scientists gather evidence to either support or refute the hypothesis. If the hypothesis is supported by the evidence, it can then be considered as a possible explanation for the observed phenomenon.
43.
Table 1
Distance Between
Object and Light (cm)
Height of Shadow
(cm)
10
32
15
27
20
25
The distances listed in Table 1 are examples of _______ data.
Correct Answer
C. Quantitative
Explanation
The distances listed in Table 1 are examples of quantitative data because they are numerical measurements that can be quantified and compared.
44.
Table 1
Distance Between
Object and Light (cm)
Height of Shadow
(cm)
10
32
15
27
20
25
A graph of the data in Table 1 would show “distances between the object and light”
variable on the ____ - axis.
Correct Answer
A. X-axis
Explanation
A graph of the data in Table 1 would show the "distances between the object and light" variable on the x-axis because the x-axis typically represents the independent variable or the variable that is being manipulated or controlled in an experiment. In this case, the distance between the object and light is the independent variable, and it is being changed or varied in the experiment. The y-axis, on the other hand, usually represents the dependent variable or the variable that is being measured or observed. In this case, the height of the shadow is the dependent variable, which is being measured based on the different distances between the object and light.
45.
Table 1
Distance Between
Object and Light (cm)
Height of Shadow
(cm)
10
32
15
27
20
25
The height of shadow would be the _____ variable.
Correct Answer
A. Responding (dependent)
Explanation
The height of the shadow is the responding (dependent) variable because it is the variable that is being measured and observed in response to the distance between the object and the light. The distance between the object and the light is the manipulated (independent) variable because it is being intentionally changed or manipulated in the experiment. The controlled variable refers to any other factors that are kept constant in the experiment to ensure that they do not affect the results.
46.
Which of these is a qualitative observation?
Correct Answer
B. The candle material melts when heated.
Explanation
The statement "The candle material melts when heated" is a qualitative observation because it describes a physical change in the candle material when it is exposed to heat. Qualitative observations are based on the qualities or characteristics of an object or phenomenon, rather than on numerical measurements or quantities. In this case, the observation is focused on the change in state of the candle material, which is a qualitative characteristic.
47.
Which of these is a conclusion?
Correct Answer
C. The candle needs oxygen to burn.
Explanation
The conclusion can be inferred from the given information because it states that the candle needs oxygen to burn. This conclusion is based on the general knowledge that combustion requires oxygen.