First Semester Physical Science Review

An element is a substance that is made up of only one kind of atom. It cannot be broken down into simpler substances by chemical means. Elements are the building blocks of all matter and are represented by symbols on the periodic table.

Metal is the correct answer because it is malleable, meaning it can be easily bent or shaped without breaking. Metals also have high electrical conductivity, allowing them to conduct electricity effectively. Wood, paper plates, and blocks of ice do not possess these properties, making them unsuitable choices for the given statement.

Protons are positively charged particles found inside the nucleus of an atom. Electrons are negatively charged particles that orbit the nucleus, while neutrons have no charge and are also found in the nucleus. Therefore, the correct answer is proton.

Atoms are the smallest units of matter that retain the chemical properties of an element. They consist of a nucleus, which contains positively charged protons and uncharged neutrons, surrounded by negatively charged electrons. Atoms combine to form molecules and compounds, making them the fundamental building blocks of all matter.

Qualitative observations are based on the use of our five senses, including sight, hearing, touch, taste, and smell. These observations involve subjective descriptions and interpretations of the characteristics or qualities of an object or event. By relying on our senses, we can gather information about the properties, appearances, textures, sounds, flavors, and odors of things around us. Therefore, it is accurate to say that qualitative observations are made using our five senses, making the statement "True" correct.

Mass is not a chemical property because it is a physical property that can be measured and does not involve any chemical reactions or changes in the composition of a substance. Chemical properties, on the other hand, describe how a substance interacts with other substances and involve the formation or breaking of chemical bonds. Flammability, reactivity, and combustibility are all examples of chemical properties as they describe how a substance reacts with fire or other chemicals.

In an experiment, the independent variable is the factor that the researcher deliberately manipulates or changes in order to observe its effect on the dependent variable. The dependent variable, on the other hand, is the variable that is observed and measured to determine the outcome or response of the experiment. Therefore, the independent variable can be changed, while the dependent variable responds to these changes.

Trail mix is an example of a heterogeneous mixture because it is made up of different components that can be easily distinguished from one another. It typically contains a combination of nuts, dried fruits, seeds, and sometimes chocolate or candy. Each component retains its own physical properties and can be visually identified within the mixture. In contrast, water, jello, and cool whip are examples of homogeneous mixtures as they are uniform throughout and do not have visibly distinguishable components.

Electrons are negatively charged particles with negligible mass compared to protons and neutrons. They are found outside the nucleus in electron shells or energy levels. This is in contrast to protons and neutrons, which are located within the nucleus of an atom. Therefore, the correct answer is electron.

Gases are compressible because their particles are far apart and have a lot of empty space between them. When pressure is applied to a gas, the particles can be pushed closer together, reducing the volume of the gas. This is not possible in solids and liquids because their particles are tightly packed and have less empty space between them, making them less compressible.

Gas is the state of matter in which molecules have a high degree of freedom and are not strongly bound to each other. This allows them to move freely and fill any container they are placed in. In contrast, solids have tightly packed molecules that cannot move freely, liquids have molecules that are loosely packed but still have some degree of attraction, and plasma is a highly ionized gas that is not commonly found on Earth. Therefore, gas is the state of matter in which molecules can fill any container.

When the forward and reverse paths of a change occur at the same rate, it indicates that the system is in equilibrium. In an equilibrium state, there is a balance between the forward and reverse reactions, resulting in no net change in the system's properties. This means that the system is stable and there is no overall change occurring.

Nobel Gases are stable and have full outer shells. This is because they have a complete set of valence electrons, making them unreactive and less likely to form chemical bonds with other elements. The full outer shells provide stability to the atoms of noble gases, making them inert and non-reactive under normal conditions.

The given statement suggests that the atoms are fixed in position, indicating a strong intermolecular force. However, it also mentions that there is some movement or jiggling happening within the substance. This behavior is characteristic of solids, as the atoms are closely packed and vibrate in place. In liquids and gases, the atoms have more freedom to move and are not fixed in position. Plasma, on the other hand, consists of charged particles and does not have fixed positions for atoms. Therefore, the correct answer is solid.

The correct answer is pure substances and mixtures. This classification is based on the composition of matter. Pure substances are made up of only one type of atom or molecule and cannot be separated into other substances by physical means. Mixtures, on the other hand, are composed of two or more substances that are physically combined and can be separated by physical means.

The statement "A liquid has no definite volume or shape" is incorrect. Liquids do have a definite volume, meaning they take up a specific amount of space. However, liquids do not have a definite shape, as they can take the shape of their container. Therefore, the correct answer is False.

The formation of a precipitate, which is a solid formed from the reaction of two liquids, indicates a chemical change. This is because the reaction between the two liquids results in the formation of a new substance with different properties. The other options, such as the temperature staying the same or the color change of a rock, do not necessarily indicate a chemical change as they can be attributed to physical changes or other factors.

The mass of an atom is made up of protons and neutrons. Protons have a positive charge and are located in the nucleus of the atom, while neutrons have no charge and are also found in the nucleus. Electrons, on the other hand, have a negative charge and orbit around the nucleus in energy levels, but they contribute very little to the overall mass of the atom. Therefore, the correct answer is protons and neutrons.

An acid is a substance that tastes sour, has a pH value between 1 and 7, and feels squeaky. Acids have a sour taste due to the release of hydrogen ions when dissolved in water. The pH scale measures the acidity or alkalinity of a substance, and a pH value between 1 and 7 indicates acidity. Acids can also feel squeaky when touched due to their corrosive nature. The statement "produces OH" is incorrect because acids actually produce H+ ions, not OH- ions.

Bases are substances that have a pH greater than 7 and are characterized by certain properties. One property of bases is that they feel slimy or soapy to the touch. Another property is that they taste bitter. Lastly, bases have a pH ranging from 7 to 14, which means they are alkaline. Therefore, feeling slimy, tasting bitter, and having a pH of 7-14 are all properties of bases.