Grade 10 Science Practice Exam With Answers

A new smell can indicate that a chemical reaction has occurred.  During a chemical reaction, new substances are formed with different properties than the original substances. These new substances can have distinct odors, which can be detected by our sense of smell. Therefore, if a new smell is noticed, it suggests that a chemical reaction has taken place.

The basic unit of life in all living things is the cell. Cells are the smallest structural and functional units of organisms, capable of carrying out all the processes necessary for life. They contain genetic material, organelles, and a plasma membrane that separates the internal environment of the cell from the external environment. Cells can exist as single-celled organisms or be part of a multicellular organism, working together to perform specific functions and maintain the overall health and functioning of the organism.

A heart attack, also known as a myocardial infarction, happens when the coronary arteries, which supply blood to the heart muscle, become blocked. This blockage is usually caused by a buildup of plaque, a fatty substance, in the arteries. When the arteries are blocked, the heart muscle is deprived of oxygen and nutrients, leading to damage or death of the heart tissue. The statement that a heart attack occurs when coronary arteries get blocked is true.

Refraction is the bending of light as it passes from one medium to another. When a pencil is placed in water, the light rays from the pencil travel from air to water, causing them to change direction. This change in direction creates an optical illusion, making the pencil appear bent or broken.

In most acid/base neutralization reactions, water, and salt are products. When an acid reacts with a base, it neutralizes each other, usually resulting in the formation of water and a salt compound.  Acids release hydrogen ions (H+) and bases release hydroxide ions (OH-). When these ions combine, they form water (H2O), and the remaining positive and negative ions form a salt. 

The esophagus is the tube that leads from the throat to the stomach. It is responsible for transporting food and liquids from the mouth to the stomach for digestion. The trachea, on the other hand, is the tube that leads from the throat to the lungs and is involved in the process of breathing. The bronchioles are small branches of the bronchi in the lungs, and the nasal cavity is the hollow space behind the nose.

The mitochondria and chloroplast are mostly responsible for energy production. Mitochondria are known as the powerhouses of the cell because they generate the majority of the cell's energy through cellular respiration. Chloroplasts, on the other hand, are found in plant cells and are responsible for photosynthesis, the process by which sunlight is converted into chemical energy in the form of glucose. Both of these organelles play crucial roles in energy production within cells.

A proton is a subatomic particle that carries a positive charge. It is one of the fundamental particles found in the nucleus of an atom. The positive charge of a proton is equal in magnitude but opposite in sign to the negative charge of an electron. This charge difference between protons and electrons is what allows for the formation of electric fields and the attraction between atoms, leading to the formation of molecules and matter as we know it.

When naming molecular (covalent) compounds, prefixes are used. This is true because covalent compounds are formed by the sharing of electrons between atoms. The prefixes indicate the number of each type of atom present in the compound. These prefixes include mono-, di-, tri-, tetra-, penta-, and so on. By using these prefixes, we can accurately name and identify the different molecular compounds based on their composition.

When writing the chemical names for some transition elements, Roman numerals may be required. This is because transition elements can form multiple ions with different charges. The Roman numerals indicate the charge of the ion. For example, iron can form ions with a charge of +2 or +3, so the chemical names for these ions would be iron(II) and iron(III), respectively. 

Light passes through transparent materials most easily because they allow light to pass through without scattering or absorbing it. Transparent materials have a high degree of clarity, allowing light to travel through them with minimal obstruction. This is in contrast to translucent materials, which allow some light to pass through but scatter it in different directions, and opaque materials, which allow very little light to pass through at all. Reflective materials, on the other hand, reflect light back rather than allowing it to pass through.

The gall bladder, pancreas, and liver are not directly involved in the passage of ingested food. The gall bladder stores bile produced by the liver. The pancreas produces digestive enzymes.  The liver produces bile. The correct answer, "None of the above," implies that the passage of ingested food does not involve any of these organs.

The given answer "all of the above" is correct because veins contain deoxygenated blood have valves that prevent backflow, and are under less pressure than arteries. Veins carry deoxygenated blood back to the heart, which gives them a bluish appearance. The valves in veins ensure that blood flows in one direction, preventing any backflow. Additionally, veins have thinner walls and lower pressure compared to arteries because they do not need to withstand as much force from the heart's contractions. Therefore, all the statements mentioned in the question are true for veins.

Copper (I) bromide is a compound formed by the combination of copper and bromine. In this compound, copper has a +1 oxidation state, indicated by the Roman numeral I in parentheses. Bromine has a -1 oxidation state. The chemical formula CuBr represents one copper atom bonded to one bromine atom, which satisfies the valency requirements of both elements. Therefore, CuBr is the correct chemical formula for copper (I) bromide.

The atomic mass of an element is an average of the atomic masses of all of the isotopes of that element occurring in nature. Isotopes are atoms of the same element that have different numbers of neutrons. Since different isotopes of an element have different masses, the atomic mass is calculated by taking into account the abundance of each isotope and its respective mass. This results in a decimal value for the atomic mass, rather than a whole number.

A group of tissues working together to perform a common function is called an organ. This is because organs are composed of different types of tissues that work together to carry out specific functions in the body.

Large vessels that carry blood away from the heart are called arteries. Arteries have thick, muscular walls that allow them to withstand the high pressure of blood being pumped by the heart. They transport oxygenated blood to various parts of the body, delivering nutrients and oxygen to the tissues. Unlike veins, arteries carry oxygen-rich blood, and they play a crucial role in maintaining the circulatory system's overall function.

Plant cells are different from animal cells because they have cell walls, which provide structural support and protection. They also have a large vacuole, which helps maintain turgor pressure and store water, nutrients, and waste products. Additionally, plant cells have chloroplasts, which are responsible for photosynthesis and contain chlorophyll. Therefore, all of the given options are correct and contribute to the unique characteristics of plant cells.

The correct answer is "all of the above" because all three options mentioned, namely heartbeat, diaphragm, and internal anal sphincter, are involved in involuntary contraction and relaxation. The heartbeat is controlled by the autonomic nervous system and occurs without conscious control. The diaphragm is a muscle involved in the process of breathing, which is also an involuntary action. The internal anal sphincter is a smooth muscle that helps regulate the passage of stool and is under involuntary control., All three options are correct.

The given statement is false because compounds that only contain non-metals are called covalent compounds, not ionic compounds. Ionic compounds are usually formed when a metal and a nonmetal combine through ionic bonding, while covalent compounds are usually formed when nonmetals share electrons through covalent bonding.

Oxygen travels through the lungs from the bronchus to the bronchiole to the alveoli. The bronchus is the main airway that leads from the trachea into the lungs. It branches into smaller tubes called bronchioles, which further divide into tiny air sacs called alveoli. In the alveoli, oxygen is exchanged with carbon dioxide in the capillaries.

A positively charged ion is called a cation, not an anion. An anion is a negatively charged ion. Therefore, the statement is incorrect.

Wood burning is an example of a chemical property because it involves a chemical reaction. When wood is exposed to heat, it undergoes combustion, breaking down its chemical structure and releasing energy in the form of heat and light. This process is irreversible and results in the formation of new substances, such as carbon dioxide and water vapor.

False. The production of light by living things is not called incandescence. It is known as bioluminescence. Incandescence refers to the emission of light as a result of high temperature, often associated with heated solid objects, while bioluminescence is the ability of living organisms to produce light through chemical reactions.

A cell spends most of its life in interphase

Noble gasses have elements with full valence shells. Valence shells are the outermost electron shells of an atom, and having a full valence shell makes an element stable and less likely to react with other elements. Noble gasses, such as helium, neon, and argon, have full valence shells, which is why they are chemically unreactive.

A compound is formed when 2 or more elements are combined together. In chemistry, elements can react with each other to form compounds through chemical reactions. These compounds have their own unique properties and characteristics that are different from the elements they are made up of. Compounds are formed by the sharing, gaining, or losing of electrons between the atoms of different elements, resulting in the formation of new chemical bonds. This process allows for the creation of a wide variety of compounds with different compositions and structures.

Incandescence is the emission of light from a hot object due to its high temperature. All the listed options produce light through this process:

Coals in a wood stove glow red-hot.

Sparks from grinding metal emit light due to intense heat.

A filament light bulb works by heating a metal filament until it glows.

Thus, all of the above involve incandescence and are correct examples.

An atom becomes charged when it gains or loses electrons. A charged atom is called an ion. Ions can be positively charged if they lose electrons, or negatively charged if they gain electrons. The term "ion" is used to refer to both positively and negatively charged atoms.

During anaphase, the chromosomes move toward opposite ends of the cell. This is facilitated by the spindle fibers, which attach to the centromeres of the chromosomes and pull them apart. As the spindle fibers shorten, the chromosomes are separated and move towards the poles of the cell. This process ensures that each daughter cell receives a complete set of chromosomes during cell division.

When light speeds up, it bends away from the normal angle. This is because of the change in the speed of light when it travels from one medium to another. When light enters a medium with a higher refractive index, it slows down and bends towards the normal. Conversely, when light enters a medium with a lower refractive index, it speeds up and bends away from the normal. In this case, since the light is speeding up, it will bend away from the normal.

Glow sticks are an example of chemiluminescence because they produce light through a chemical reaction. Inside a glow stick, there are two separate compartments containing chemicals. When the stick is bent, the compartments break and the chemicals mix together. This mixing triggers a reaction that releases energy in the form of light.

In a chemical reaction, the substances that undergo a change are known as reactants. The reactants are the starting materials that react with each other to form new substances. Reactants are consumed during the reaction and are transformed into products. 

Radio waves have the longest wavelength among the given options. Radio waves have wavelengths ranging from about one millimeter to hundreds of kilometers, making them longer than microwaves, ultraviolet rays, and visible light. This longer wavelength allows radio waves to travel long distances and penetrate through obstacles, making them ideal for communication purposes such as radio broadcasting and wireless communication.

Elements in the same vertical column on the periodic table, also known as groups or families, have the same number of valence electrons. Valence electrons are the electrons in the outermost energy level of an atom and are responsible for the chemical properties of the element. Elements in the same group have similar chemical behavior because they have the same number of valence electrons, which determines how they interact with other atoms to form compounds. 

Diamond would be expected to have the highest index of refraction because it is a dense material with a high optical density. The index of refraction is a measure of how much light is bent or refracted when it passes through a medium. Since diamond has a high index of refraction, it means that light will be bent more when it passes through diamond compared to the other materials listed (water, air, and acrylic). This property of diamond makes it highly valued in the field of optics and is one of the reasons why it is commonly used in jewelry and cutting tools.

Prokaryotic cells differ from eukaryotic cells in that they lack a nucleus. While eukaryotic cells have a well-defined nucleus that houses the genetic material, prokaryotic cells do not possess a true nucleus. Instead, their DNA is found in a region called the nucleoid, which is not enclosed by a membrane. This distinction is one of the defining characteristics of prokaryotic cells and is a fundamental difference between the two types of cells.

A negative ion is created when an atom gains electrons. When an atom gains one or more electrons, it becomes negatively charged because the number of negatively charged electrons now exceeds the number of positively charged protons in the atom. This creates an imbalance of charges, resulting in the formation of a negative ion.

The term "pH" stands for "potential of Hydrogen" or "power of Hydrogen." It is a measure of the hydrogen ion concentration in a solution, which determines its acidity or alkalinity on the pH scale. The pH scale ranges from 0 to 14, with 7 being neutral, values below 7 indicating acidity, and values above 7 indicating alkalinity.

A covalent bond is formed when two atoms share electrons. In this case, a chlorine atom and another chlorine atom would most likely form a covalent bond because both chlorine atoms have the same electronegativity, meaning they have similar tendencies to attract electrons. This allows them to share electrons equally and form a stable molecule. On the other hand, bonds between chlorine and magnesium, chlorine and iron, or sodium and fluorine would be less likely to be covalent due to the significant difference in electronegativity between these elements.

When forming compounds, metal elements tend to lose electrons. This is because metals have fewer valence electrons, which are the electrons in the outermost energy level of an atom. By losing these electrons, metals can achieve a stable electron configuration similar to that of a noble gas. This process of losing electrons is known as oxidation and allows metals to form positive ions, which can then bond with other elements to form compounds.

Peristalsis is the coordinated muscular contraction and relaxation that propels materials through the digestive tract. It is a characteristic action of organs such as the esophagus, stomach, and intestines. Smooth muscle tissue is responsible for this rhythmic movement, as it is capable of involuntary contractions. Cartilage, epithelial tissue, and connective tissue do not have the contractile ability required for peristalsis.

False. A convex mirror is also known as a diverging mirror. Convex mirrors curve outward, causing parallel light rays to diverge. They have a reflective surface that bulges outward, and they are commonly used in applications such as side mirrors on vehicles to provide a wider field of view.

False. Epithelial, connective, and nervous tissues are three of the four primary types of animal tissues. Vascular tissues are not a type of animal tissue. The fourth type is muscle tissue. So, the four types of animal tissues are epithelial, connective, muscle, and nervous tissues.

NaCl dissolving easily in water does not represent a chemical change, it is a physical change. Dissolving is a process where molecules are separated and dispersed in the water, but no new substances are formed.  NaCl reforms into the same substance when water containing it is evaporated.

As the index of refraction increases, the speed of light slows down. This is because the index of refraction is a measure of how much a material can slow down the speed of light as it passes through it. When light travels from a medium with a lower index of refraction to a medium with a higher index of refraction, it slows down due to interactions with the atoms or molecules in the material. 

Sulfur and potassium would be most likely to combine to form an ionic bond. This is because sulfur has six valence electrons and can gain two electrons to achieve a stable octet, while potassium has one valence electron and can easily lose it to achieve a stable octet. This transfer of electrons from potassium to sulfur would result in the formation of an ionic bond between the two elements. The electronegativity difference between sulfur, an electronegative element, and potassium, an electropositive element, is high.

A diverging mirror will always produce a smaller, upright, behind, virtual image. Diverging mirrors are curved mirrors that bulge outwards, causing light rays to spread out. This spreading out of light rays results in a smaller image being formed compared to the object. The image formed by a diverging mirror is always upright, meaning it is not inverted. Additionally, the image is formed behind the mirror, indicating that it is a virtual image.