1.
Which of the following is not a part of the scientific method?
Correct Answer
C. Proving
Explanation
Proving is not a part of the scientific method because science does not aim to prove things definitively. Instead, it seeks to gather evidence through experimentation, observation, and hypothesis testing to support or reject a hypothesis. The scientific method involves formulating a hypothesis based on observations, conducting experiments to test the hypothesis, and analyzing the results to draw conclusions. The goal is to generate reliable and reproducible knowledge, rather than proving something beyond a doubt.
2.
Which of the following is the main component of biogas?
Correct Answer
D. Methane
Explanation
Biogas is primarily composed of methane (CH4). Methane is the main component of biogas because it is produced through the anaerobic digestion of organic materials by microorganisms in the absence of oxygen. These microorganisms break down organic matter, such as agricultural waste, sewage, and food scraps, and produce methane gas as a byproduct of their metabolic processes. Methane is a potent greenhouse gas and a valuable source of renewable energy when captured and used as biogas, contributing to sustainable waste management and renewable energy production.
3.
Which of the following compounds is a noble gas?
Correct Answer
D. Helium
Explanation
Helium is the only compound listed that is a noble gas on the furthest right period of the periodic table. Noble gases are a group of elements on the periodic table that are known for their low reactivity and stable electron configurations. Helium is the second lightest element and is colorless, odorless, and tasteless. It is commonly used in balloons and as a cooling agent in various industries.
4.
Who came forward with the atomic theory?
Correct Answer
B. John Dalton
Explanation
John Dalton came forward with the atomic theory. Dalton was an English chemist and physicist who proposed the theory in the early 19th century. He suggested that all matter is made up of tiny, indivisible particles called atoms, which combine in specific ratios to form compounds. Dalton's theory laid the foundation for modern atomic theory and revolutionized our understanding of the composition and behavior of matter. His work has had a significant impact on the fields of chemistry and physics.
5.
Which of the following compounds is known as "laughing Gas"?
Correct Answer
A. Nitrous oxide
Explanation
Nitrous oxide is known as "laughing gas" because it has a euphoric effect on the human body when inhaled. It is commonly used as an anesthetic and analgesic in medical and dental procedures. The name "laughing gas" comes from the gas's ability to induce laughter and a sense of euphoria in patients.
6.
What is the scientific name of vinegar?
Correct Answer
D. Acetic acid
Explanation
Vinegar is a common household product that is primarily composed of acetic acid. Acetic acid is a weak acid that is produced through the fermentation process of ethanol by an acetic acid bacteria. It is the main component responsible for the sour taste and pungent smell of vinegar.
7.
Which of these steps of the scientific method involves stating a
relationship but not proposing an explanation for the relationship?
Correct Answer
C. Theory
Explanation
A theory in the scientific method involves stating a relationship without proposing an explanation for the relationship. Theories are based on extensive research and evidence, and they provide a framework for understanding and explaining a phenomenon. Unlike hypotheses, which propose a specific explanation that can be tested, theories are broader and more general, providing a conceptual understanding of how different variables or factors are related. Theories can be revised or refined as more evidence is gathered, but they do not provide a specific explanation for the relationship they state.
8.
These are the three primary states of matter that exist on Earth.
Correct Answer
B. Solid, liquid, and gas
Explanation
The correct answer is solid, liquid, and gas. These are the three states of matter commonly known and studied in science. Solids have a definite shape and volume, liquids have a definite volume but take the shape of their container, and gases have neither definite shape nor volume. This classification is based on the arrangement and movement of particles in each state.
9.
A liquid has:
Correct Answer
B. A definite volume, but not a definite shape
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 change its shape to fit the container it is in. The particles in a liquid are close together but still able to move past each other, allowing the liquid to flow and take the shape of its container.
10.
Which of the following is a list of compounds?
Correct Answer
A. Water, carbon dioxide, benzene
Explanation
Water, carbon dioxide and benzene are all examples of compounds because they are made up of two or more different elements chemically combined together. Water is composed of hydrogen and oxygen; carbon dioxide is composed of carbon and oxygen; and benzene is composed of carbon and hydrogen. Gold, silver, brass, brick, sand, concrete, hydrogen, nitrogen, and oxygen are not compounds because they are either elements or mixtures of elements.
11.
The temperature at which a substance changes from a liquid to a gas, is the
Correct Answer
C. Boiling point
Explanation
The boiling point is the temperature at which a substance changes from a liquid to a gas. At this temperature, the vapor pressure of the substance becomes equal to the atmospheric pressure, causing the liquid to evaporate and form a gas. It is an important property of a substance as it determines its ability to vaporize and is used in various applications such as cooking, distillation, and industrial processes.
12.
Any substance that has a definite volume but no definite shape is a
Correct Answer
B. Liquid
Explanation
A liquid is a substance that has a definite volume but no definite shape. Unlike solids, which have a fixed shape and maintain their shape even when moved or poured, liquids take the shape of their container. They are able to flow and are not rigid like solids. Gases, on the other hand, have neither a definite shape nor a definite volume.
13.
Density is a measure of how much mass is contained in a given unit volume.
Correct Answer
A. True
Explanation
Density is indeed a measure of how much mass is contained in a given unit volume. It is calculated by dividing the mass of an object by its volume. The higher the density, the more mass is packed into a specific volume, while lower density means less mass is packed into the same volume.
14.
The amount of space something takes up is known as
Correct Answer
B. Volume
Explanation
Volume refers to the amount of space that an object occupies. It is a measure of the three-dimensional size of an object or substance. Density, mass, and force are not directly or indirectly related to the amount of space occupied by an object, making them incorrect choices.
15.
The temperature at which a substance changes from a solid to a liquid.
Correct Answer
D. Melting point
Explanation
The melting point is the temperature at which a substance changes from a solid to a liquid. It is the temperature at which the intermolecular forces holding the particles together in a solid are overcome, allowing the substance to transition into a liquid state.