1.
____of substance, like color, size, and hardness, can be found without changing the substance into something else.
Correct Answer
B. pHysical Properties
Explanation
Physical properties are characteristics of a substance that can be observed or measured without changing the substance into something else. Examples of physical properties include color, size, and hardness. Reactivity, chemical properties, and evaporation involve changes in the substance and are not considered physical properties.
2.
Sometimes the ability to be dissolved called ________, can be used to identify a substance.
Correct Answer
A. Solubility
Explanation
Solubility refers to the ability of a substance to dissolve in a solvent. It is a physical property that can be used to identify and characterize substances. By observing whether a substance dissolves or not in a particular solvent, one can determine its solubility and potentially identify the substance. Therefore, solubility is the correct answer as it accurately describes the property being discussed in the question.
3.
Chemical changes can turn substances into other substances. The ability of a substance to go through a chemical change is called _____.
Correct Answer
D. Reactivity
Explanation
Chemical changes involve the transformation of substances into different substances. The term used to describe the ability of a substance to undergo a chemical change is "reactivity". Reactivity refers to the tendency of a substance to react with other substances and undergo chemical reactions. This can result in the formation of new compounds or the breaking down of existing compounds. Therefore, the correct answer is reactivity.
4.
The amount of material in an object is called the object's _____.
Correct Answer
D. Mass
Explanation
Mass is the correct answer because it refers to the amount of material in an object. It is a measure of the inertia of an object and is commonly measured in units such as kilograms or grams. Mass is independent of the object's location or the gravitational force acting on it. It is an intrinsic property of an object and can be used to determine the object's resistance to changes in motion.
5.
All material that has mass and takes up space is called.
Correct Answer
B. Matter
Explanation
Matter is the correct answer because it refers to any substance that has mass and occupies space. It includes everything around us, such as solids, liquids, and gases. Mass, weight, and solubility are all properties or characteristics of matter, but they do not encompass the entire definition of matter itself.
6.
____ has a definate volume but no definite shape.
Correct Answer
B. Liquid
Explanation
A liquid has a definite volume because it takes up a specific amount of space, but it does not have a definite shape because it can flow and take the shape of its container. Unlike solids, which have a fixed shape, and gases, which can expand to fill any space, liquids maintain their volume while adapting to the shape of their container. Therefore, a liquid is the correct answer for this question.
7.
Which of the following does not signal a chemical change?
Correct Answer
A. Change in state
Explanation
A change in state does not signal a chemical change because it is a physical change. When a substance changes from a solid to a liquid or a gas, or vice versa, the chemical composition of the substance remains the same. In a chemical change, the substances involved undergo a rearrangement of atoms, resulting in the formation of new substances with different chemical properties. Therefore, the other options (production of gas, color change, production of light and heat) all indicate chemical changes as they involve the formation of new substances.
8.
When iron rusts, it no longer conducts electricity. This is because it---
Correct Answer
B. Changed Chemically
Explanation
Iron rusting involves a chemical reaction where iron reacts with oxygen in the presence of water to form iron oxide. This process is known as oxidation. As a result of this chemical change, the iron surface is covered with a layer of iron oxide, which is a poor conductor of electricity compared to pure iron. Therefore, when iron rusts, it no longer conducts electricity due to the chemical changes that have occurred.
9.
In which of the case below, is a substance undergoing a chemical change?
Correct Answer
C. Burning wood
Explanation
Burning wood is a chemical change because it involves a chemical reaction that results in the release of heat, light, and the formation of new substances. The wood undergoes combustion, breaking down its organic compounds and transforming into ash, smoke, and gases such as carbon dioxide and water vapor. This is different from physical changes like grinding coffee beans, melting butter, or boiling water, where the substances may change in form or state but do not undergo a chemical reaction to form new substances.
10.
Which of the following is Not a physical property?
Correct Answer
C. Reactivity
Explanation
Reactivity is not a physical property because it refers to how a substance undergoes chemical reactions or interacts with other substances. Physical properties, on the other hand, are characteristics that can be observed or measured without changing the substance's chemical composition. Solubility, density, and color are all examples of physical properties as they can be determined without altering the substance's chemical makeup.
11.
Check box that has pure substances.
Correct Answer
A. Table salt
Explanation
Table salt is a pure substance because it is made up of only one type of molecule, sodium chloride. It does not contain any other substances or impurities. In contrast, air is a mixture of gases, fruit salad is a mixture of different fruits, and pizza is a combination of various ingredients such as dough, cheese, and toppings. Therefore, only table salt qualifies as a pure substance.
12.
A set of guidelines used by scientists to answer questions about a problem refers to:
Correct Answer
B. The scientific method
Explanation
The scientific method is a set of guidelines used by scientists to answer questions about a problem. It involves a systematic approach of making observations, formulating hypotheses, conducting experiments, analyzing data, and drawing conclusions. This method ensures that scientific investigations are conducted in a logical and objective manner, allowing for the replication and verification of results. Opinion sharing, logical thinking, and daydreaming are not specific methods used by scientists to answer questions, making them incorrect options.
13.
2.98672 X 10*8 rounded to four significant figures is ------
Correct Answer
D. 2.987 x 10*8
Explanation
The given number, 2.98672 x 10^8, needs to be rounded to four significant figures. The significant figures are the non-zero digits in a number, as well as any zeros between them. In this case, the first four digits, 2.986, are non-zero digits and are significant. The next digit, 7, is greater than 5, so we round up the last significant digit, which is 6, to 7. Therefore, the rounded number to four significant figures is 2.987 x 10^8.
14.
The number that has 3 significant figures is -----
Correct Answer
B. 234000
Explanation
The number 234000 has 3 significant figures because all the zeros between the non-zero digits are also considered significant. In this case, there are 3 non-zero digits (2, 3, and 4) and no trailing zeros after the decimal point, so all the zeros are significant. Therefore, the number has 3 significant figures.
15.
The correct number of significant figures that appears in the answer to the calculations 1.870 X 2.313 X 7.82
Correct Answer
A. 3
Explanation
The given calculation involves multiplying three numbers: 1.870, 2.313, and 7.82. The rule for determining the number of significant figures in a multiplication or division is to count the number of significant figures in each number and choose the lowest count. In this case, the first number has four significant figures, the second number has three significant figures, and the third number has three significant figures. Therefore, the answer should have three significant figures, which matches the given correct answer of 3.
16.
The correct number of significant figures that appears in the decimal spot of answer to the calculations 4.21 + 2.3 + 5.210
Correct Answer
B. 1
Explanation
The correct answer is 1 because when adding or subtracting numbers, the answer should have the same number of decimal places as the number with the fewest decimal places. In this case, 2.3 has only one decimal place, so the answer should also have one decimal place.
17.
------- is not the unit used for measuring temperature.
Correct Answer
D. Kilogram
Explanation
Kilogram is a unit used for measuring mass, not temperature. Temperature is typically measured in Fahrenheit, Celsius, or Kelvin.
18.
A hypothesis is most closely related to which of the following?
Correct Answer
B. An educated prediction
Explanation
A hypothesis is a proposed explanation or prediction based on limited evidence or observation. It is an educated prediction because it is formed through careful observation, background knowledge, and logical reasoning. A hypothesis is a starting point for further investigation and testing, and it can be supported or refuted by empirical evidence. Therefore, it is most closely related to an educated prediction rather than a theory, a wild guess, or a law, which are more comprehensive and established concepts in scientific research.
19.
In an experiment, the variable that responds to any change in the variable being manipulated is:
Correct Answer
C. Dependent variable
Explanation
The dependent variable is the variable that is affected or influenced by the changes made to the independent variable. It is called "dependent" because its value depends on the manipulation of the independent variable. In an experiment, researchers manipulate the independent variable to observe how it affects the dependent variable. Therefore, the correct answer is the dependent variable.
20.
Graphs, charts, and calculations are representation of what form of data?
Correct Answer
A. Quantitative data
Explanation
Graphs, charts, and calculations are tools used to represent quantitative data. Quantitative data is numerical and can be measured or counted. These visual representations are used to display and analyze data such as measurements, quantities, or statistical information.
21.
In testing whether plants will grow better if you play music for them on a daily basis, which of the following would be the control group?
Correct Answer
A. A group of plants that are watered daily and receive ample light in a room with no music playing.
Explanation
The control group in this experiment is the group of plants that are watered daily and receive ample light in a room with no music playing. This group is the control because it represents the standard conditions that the other groups will be compared to. By not playing music in this group, we can isolate the effect of music on plant growth and determine if it has any impact compared to the control group.
22.
(5.87 X 10*5) X (2.56 X 10*4) =
Correct Answer
1.50 x 10*10
1.50272 x 10*10
Explanation
The given expression is a multiplication of two numbers in scientific notation. To multiply numbers in scientific notation, we multiply the coefficients and add the exponents.
In this case, (5.87 X 10^5) X (2.56 X 10^4) can be simplified as (5.87 X 2.56) X (10^5 X 10^4).
Multiplying the coefficients, we get 15.0272.
Adding the exponents, we get 10^5 + 10^4 = 10^9.
Therefore, the final answer is 1.50272 x 10^9, which matches the second option provided.
23.
(5.98 X 10*4) / (1.43 X 10*2)
Correct Answer
4.18 X 10*2
Explanation
The given expression is a division of two numbers in scientific notation. To divide numbers in scientific notation, we subtract the exponent of the divisor from the exponent of the dividend and divide the coefficients. In this case, (5.98 / 1.43) gives us 4.18, and (10*4 / 10*2) simplifies to 10*2. Therefore, the answer is 4.18 X 10*2.
24.
The term 'ATOMOS' was coined by:
Correct Answer
Democritus
Explanation
Democritus coined the term 'ATOMOS'. Democritus was an ancient Greek philosopher who proposed the concept of atoms as the fundamental building blocks of matter. He believed that all matter consisted of indivisible and indestructible particles called atoms. Democritus' atomic theory was based on the idea that atoms are constantly moving and combining to form different substances. His contributions to the understanding of atoms laid the foundation for modern atomic theory.
25.
Neutrons were discovered by:
Correct Answer
C. Chadwick
Explanation
Chadwick is the correct answer because he was the scientist who discovered the existence of neutrons in 1932. Through his experiments, Chadwick observed that when beryllium was bombarded with alpha particles, a neutral radiation was emitted. He concluded that this neutral radiation consisted of particles with no charge, which he named neutrons. This discovery was crucial in understanding the structure of the atom and led to the development of nuclear physics.
26.
The gold foil experiment was conducted by:
Correct Answer
B. Ernest Rutherford
Explanation
Ernest Rutherford conducted the gold foil experiment. This experiment involved firing alpha particles at a thin sheet of gold foil to study the structure of atoms. Rutherford's observations led to the discovery of the atomic nucleus and the concept of the nuclear model of the atom. He found that most of the alpha particles passed straight through the foil, suggesting that atoms are mostly empty space. However, a small fraction of the particles were deflected at large angles, indicating the presence of a dense, positively charged nucleus at the center of the atom.
27.
Who proposed the Modern Atomic Theory?
Correct Answer
D. John Dalton
Explanation
John Dalton proposed the Modern Atomic Theory. This theory states that all matter is made up of tiny indivisible particles called atoms, which cannot be created or destroyed. Dalton's theory also suggested that atoms of different elements have different properties and combine in specific ratios to form compounds. His work laid the foundation for our understanding of the structure and behavior of atoms, and it revolutionized the field of chemistry.
28.
The element with atomic number 26 is:
Correct Answer
B. Iron
Explanation
The element with atomic number 26 is iron. Atomic number represents the number of protons in an atom's nucleus, and iron has 26 protons. Magnesium has an atomic number of 12, Mathematica is not an element but a software program, and chlorine has an atomic number of 17. Therefore, the correct answer is iron.
29.
Chemical symbol of metal copper is:
Correct Answer
B. Cu
Explanation
The chemical symbol of the metal copper is Cu.
30.
The ________ is the identity of an element.
Correct Answer
B. Atomic Number
Explanation
The atomic number is the identity of an element because it represents the number of protons in the nucleus of an atom. Each element has a unique atomic number, which determines its position on the periodic table and distinguishes it from other elements. The atomic number also indirectly provides information about the number of electrons in an atom, as in a neutral atom, the number of electrons is equal to the number of protons. Therefore, the atomic number plays a crucial role in defining the characteristics and properties of an element.
31.
If you know only the following information can you always determine what the element is? Check all the answers that you agree with:
Correct Answer(s)
A. Number of protons
C. Number of electrons in a neutral atom
Explanation
The number of protons determines the element because it defines the atomic number, which is unique to each element. The number of electrons in a neutral atom is also important because it is equal to the number of protons, ensuring that the atom has a balanced charge. Therefore, knowing both the number of protons and the number of electrons in a neutral atom allows us to determine the element.
32.
A neutral atom with atomic number 15 will have _____ number of electrons
Correct Answer
B. 15
Explanation
The number of electrons in a neutral atom is equal to its atomic number. In this case, the atomic number is given as 15, so the neutral atom will have 15 electrons.
33.
The charge on electrons is ____
Correct Answer
Negative
Explanation
The charge on electrons is negative because electrons are negatively charged particles. In an atom, electrons orbit around the nucleus, which contains positively charged protons and neutral neutrons. The negative charge of electrons balances out the positive charge of protons, resulting in an overall neutral charge for the atom.
34.
The atomic number tells you the number of _________ in one atom of an element.
Correct Answer
Protons
Explanation
The atomic number of an element represents the number of protons in one atom of that element. Protons are positively charged particles found in the nucleus of an atom. Each element has a unique atomic number, which determines its placement on the periodic table and its chemical properties. Therefore, the correct answer is "Protons."
35.
The atomic number gives the “identity“ of an element as well as its location on the Periodic Table. No two different elements will ever have the _________ (same/ different ) atomic number.
Correct Answer
Same
Explanation
The atomic number of an element is a unique identifier that determines its position on the Periodic Table. It represents the number of protons in the nucleus of an atom, which is different for each element. Therefore, no two different elements will ever have the same atomic number.
36.
Convert the following number from scientific notation to standard notation:
2.5 x 10*-2
Correct Answer
B. .025
Explanation
The given number, 2.5 x 10*-2, is in scientific notation. In scientific notation, the number is written as a decimal number multiplied by a power of 10. To convert it to standard notation, we need to move the decimal point two places to the left because the exponent is negative. Therefore, the correct answer is .025.
37.
Check the box that has homogeneous mixture.
Correct Answer
B. Freshly brewed coffee
Explanation
Freshly brewed coffee is a homogeneous mixture because it is a uniform blend of coffee particles and water molecules. In a homogeneous mixture, the components are evenly distributed and cannot be easily distinguished from one another. In the case of coffee, the coffee grounds dissolve in the water, resulting in a uniform mixture with a consistent composition throughout. On the other hand, granite is a heterogeneous mixture as it consists of various minerals that are not uniformly distributed, and oil and water are immiscible, forming separate layers due to their different polarities.
38.
All statements of Dalton’s theory still apply today without any modifications.
Correct Answer
B. False
Explanation
This statement is false because Dalton's theory has been modified and expanded since it was first proposed. Over time, new discoveries and advancements in scientific understanding have led to modifications and refinements of Dalton's original ideas. For example, Dalton's theory did not account for the existence of isotopes or the concept of atomic structure, which have since been incorporated into our understanding of atoms. Therefore, it is incorrect to say that all statements of Dalton's theory still apply today without any modifications.
39.
Protons are the positively charged particles.
Correct Answer
A. True
Explanation
Protons are subatomic particles that carry a positive charge. They are found in the nucleus of an atom and play a crucial role in determining the atom's identity and chemical properties. Due to their positive charge, protons are attracted to negatively charged particles, such as electrons, and help to maintain the overall electrical neutrality of an atom. Therefore, the statement "Protons are the positively charged particles" is true.
40.
Neutrons are located in electron clouds around the nucleus.
Correct Answer
B. False
Explanation
Neutrons are actually located within the nucleus of an atom, along with protons. They do not exist in the electron clouds around the nucleus. The electron clouds, on the other hand, contain electrons, which have a negative charge and orbit around the nucleus. Therefore, the statement that neutrons are located in electron clouds around the nucleus is incorrect.
41.
The vertical rows on periodic table are the periods.
Correct Answer
B. False
Explanation
The vertical columns on the periodic table are actually the periods, not the vertical rows. Each period represents the energy levels or shells in which the electrons are arranged around the nucleus of an atom. The horizontal rows on the periodic table are called groups or families, and they represent elements with similar properties. Therefore, the correct answer is false.