Chemistry A Post Quiz: 50 Points

2.

A possible explanation of an observation that can be tested by scientific investigations is a(an) ____________________________. (AZ HS Science S1:C2:PO2)

Inference
Explanation
Hypothesis
Science

Correct Answer

A. Hypothesis

Explanation

A hypothesis is a possible explanation for an observation that can be tested through scientific investigations. It is a statement that proposes a relationship between variables and is based on prior knowledge or observations. By conducting experiments and gathering data, scientists can test the validity of a hypothesis and determine if it is supported or rejected. Hypotheses are an essential part of the scientific method and are used to guide research and generate new knowledge.

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3.

When matter moves from a gas to a liquid it is called _____________________. (AZ HS Science S5:C1:PO1)

Sublimation
Condensation
Deposition
Density

Correct Answer

A. Condensation

Explanation

When matter moves from a gas to a liquid, it is called condensation. This process occurs when the gas particles lose energy and come together to form liquid droplets. It is a phase change that typically happens when the temperature of a gas decreases or when the gas comes into contact with a cooler surface. Condensation is a common occurrence in our daily lives, such as when water vapor in the air condenses to form clouds or when steam from a hot shower condenses on a mirror.

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4.

A change in a substance that involves a change in the identity of the substance is _________________. (AZ HS Science S1:C5:PO2)

Chemical Change
Phase Change
Physical Property
Physical Change

Correct Answer

A. Chemical Change

Explanation

A change in a substance that involves a change in the identity of the substance is referred to as a chemical change. In a chemical change, the original substance is transformed into a new substance with different properties. This can occur through various processes such as combustion, oxidation, or decomposition. Unlike physical changes, which only alter the physical properties of a substance without changing its identity, chemical changes result in the formation of new compounds or molecules.

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5.

Sodium is a/an: (AZ HS Science S5:C1:PO4)

Element
Compound
Homogeneous mixture
Heterogeneous mixture

Correct Answer

A. Element

Explanation

Sodium is a correct answer because it is an element. Elements are substances that cannot be broken down into simpler substances by chemical means. Sodium is a highly reactive metal that is found in the periodic table with the symbol Na and atomic number 11. It is a soft, silvery-white metal that is commonly found in compounds such as table salt (sodium chloride).

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6.

Which of the following is not a fundamental particle in an atom? (AZ HS Science S5:C1:PO6)

Electron
Element
Neutron
Proton

Correct Answer

A. Element

Explanation

An element is not a fundamental particle in an atom. An atom is made up of three fundamental particles: electrons, protons, and neutrons. Electrons are negatively charged particles that orbit the nucleus of an atom. Protons are positively charged particles found in the nucleus, while neutrons are neutral particles also found in the nucleus. Elements, on the other hand, are substances made up of only one type of atom. They are identified by the number of protons in their nucleus, which determines their atomic number. Therefore, an element is not a fundamental particle itself but rather a collection of atoms with the same number of protons.

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7.

What is a negatively charged particle in an atom called? (AZ HS Science S5:C1:PO6)

Proton
Positron
Electron
Neutron

Correct Answer

A. Electron

Explanation

An electron is a negatively charged particle in an atom. It orbits around the nucleus and has a much smaller mass compared to protons and neutrons. Electrons play a crucial role in chemical reactions and the formation of chemical bonds.

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8.

An atom of an element contains eight electrons. What is the identity of this element? You can look on a periodic table to find out. (AZ HS Science S5:C1:PO3)

Flourine
Carbon
Oxygen
Nitrogen

Correct Answer

A. Oxygen

Explanation

An atom of oxygen contains eight electrons. Oxygen is an element found on the periodic table, and its atomic number is 8. The atomic number represents the number of protons in an atom, which is equal to the number of electrons in a neutral atom. Therefore, an atom of an element containing eight electrons is most likely oxygen.

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9.

What is the definition of chemical compound? (AZ HS Science S5:C1:PO4)

A subatomic particle
A combination of two protons and two electrons
A combination of two or more chemical elements
A mixture of two or more substances

Correct Answer

A. A combination of two or more chemical elements

Explanation

A chemical compound is defined as a combination of two or more chemical elements. It is formed when atoms of different elements chemically bond together to create a new substance with unique properties. This combination involves the sharing, gaining, or losing of electrons between atoms, resulting in the formation of stable molecules or ions. The composition and arrangement of atoms in a compound are fixed and consistent, giving it distinct properties different from its constituent elements.

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10.

(True or False) An ionic bond forms when one or more pairs of electrons are shared between two atoms of non-metal elements. (AZ HS Science S5:C1:PO4)

True
False

Correct Answer

A. False

Explanation

An ionic bond forms when one or more pairs of electrons are transferred from one atom to another, not shared. This occurs between a metal and a non-metal element, not between two non-metal elements. Therefore, the correct answer is False.

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Chemistry A Post Quiz: 50 Points

A description of how close a measurement is to the true value of the quantity measured. (AZ HS Science S1:C2:PO3)

Quiz Preview

A possible explanation of an observation that can be tested by scientific investigations is a(an) ____________________________. (AZ HS Science S1:C2:PO2)

When matter moves from a gas to a liquid it is called _____________________. (AZ HS Science S5:C1:PO1)

A change in a substance that involves a change in the identity of the substance is _________________. (AZ HS Science S1:C5:PO2)

Sodium is a/an: (AZ HS Science S5:C1:PO4)

Which of the following is not a fundamental particle in an atom? (AZ HS Science S5:C1:PO6)

What is a negatively charged particle in an atom called? (AZ HS Science S5:C1:PO6)

An atom of an element contains eight electrons. What is the identity of this element? You can look on a periodic table to find out. (AZ HS Science S5:C1:PO3)

What is the definition of chemical compound? (AZ HS Science S5:C1:PO4)

(True or False) An ionic bond forms when one or more pairs of electrons are shared between two atoms of non-metal elements. (AZ HS Science S5:C1:PO4)