In which state of matter are the intermolecular forces between particles in a substance the strongest?

If the cohesion between particles decreases, then the particles must be undergoing a phase change that allows particles to move farther apart. This happens when a substance vaporizes and turns from liquid to gas. Any phase change that moves to the right in the diagram above requires energy to be added to the system because the substance has more energy at the end of the phase change. The phase changes aremelting,vaporization (boiling), andsublimation. When energy is added, particles move faster and can break away from each other more easily as they move to a state of matter with a higher amount of energy. This is most commonly done by heating the substance.

Once the food has been masticated in the oral cavity (mouth), it is then swallowed and travels back into the pharynx down into the esophagus, which leads into the stomach.

After scientists were able to view cells under the microscope they formulated the cell theory. One part of this theory concluded that all cells are alive. They also represent the basic unit of life.

All living things are made of cells. Cells are the smallest structural units and basic building blocks of living things. Cells contain everything necessary to keep living things alive. Varying in size and shape, cells carry out specialized functions. This theory, or in-depth explanation, about cells consists of three parts:

• All living things are composed of one or more cells.
• Cells are alive and represent the basic unit of life.
• All cells are produced from pre-existing cells.

A neutralization reaction is a type of acid-base reaction where an acid and base react to form a salt and water.

In an aqueous solution, a base increases the hydroxide concentration (OH–), while an acid increases the hydrogen ion (H+) concentration. Sometimes,neutralization reactionsalso occur. This type of reaction happens when an acid and a base react with each other to form water and salt. Salt is typically defined as anionic compoundthat includes any cation except H+and any anion except OH–. Consider the following example of a neutralization reaction between hydrobromic acid (HBr) and potassium hydroxide (KOH).

HBr+KOH→KBr+H2O

Not all neutralization reactions proceed in the manner where all reactants are in the aqueous phase. In some chemical reactions, one reactant may be a solid. The neutralization reaction can still proceed to completion.

Inductive reasoning involves making specific observations and using them to make broad statements. The student observes that all of the tigers have the same stripe pattern. He can use this observation to make the broad statement that all the tigers’ offspring will have the same stripe pattern.

Inductive reasoninginvolves drawing a general conclusion from specific observations. This form of reasoning is referred to as the “from the bottom up” approach. Information gathered from specific observations can be used to make a general conclusion about the topic under investigation. In other words, conclusions are based on observed patterns in data.

Skeletal muscle: This muscle cell is striated, long, and cylindrical. There are many nuclei in a skeletal muscle cell. Attached to bones in the body, skeletal muscle contracts voluntarily, meaning that it is under conscious control.

Smooth muscle: This muscle consists of nonstriated muscle cells that are spindle-shaped. Like cardiac muscle cells, smooth muscle cells contain one nucleus. This muscle type is found in the walls of internal organs like the bladder and stomach. Smooth muscle contraction is involuntary and controlled by the autonomic nervous system.

Cardiac muscle: This muscle consists of muscle cells that are striated, short, and branched. These cells contain one nucleus, are branched, and are rectangular. Cardiac muscle contraction is an involuntary process, which is why it is under the control of the autonomic nervous system. This muscle is found in the walls of the heart.

The primary organ of the urinary system is the kidney. Blood from the heart flows through the kidneys via the renal artery. As blood drains from the kidney, it exits through a series of veins, the most prominent of which is the renal vein. When urine is produced, it does not drain through the tubes through which blood flows. Rather, urine flows through two ureters before emptying into the urinary bladder.

The following steps outline how the urinary system works:

• Kidney filters and excretes wastes from blood, producing urine.
• Urine flows down the ureters.
• Urine empties into the bladder and is temporarily stored.
• Bladder, when filled, empties urine out of the body via the urethra.

Unlike condensation, deposition, and melting, evaporation is dependent not only on the temperature, but also on the amount of a substance available.

Condensationis the change of a gas or vapor to a liquid. A change in the pressure and the temperature of a substance causes this change. The condensation point is the same as the boiling point of a substance. It is most noticeable when there is a large temperature difference between an object and the atmosphere. Condensation is also the opposite of evaporation.

Evaporationis the change of a liquid to a gas on the surface of a substance. This is not to be confused with boiling, which is a phase transition of an entire substance from a liquid to a gas. The evaporation point is the same as the freezing point of a substance. As the temperature increases, the rate of evaporation also increases. Evaporation depends not only on the temperature, but also on the amount of substance available.

Freezingis the change of a liquid to a solid. It occurs when the temperature drops below the freezing point. The amount of heat that has been removed from the substance allows the particles of the substance to draw closer together, and the material changes from a liquid to a solid. It is the opposite of melting.

Meltingis the change of a solid into a liquid. For melting to occur, enough heat must be added to the substance. When this is done, the molecules move around more, and the particles are unable to hold together as tightly as they can in a solid. They break apart, and the solid becomes a liquid.

Sublimationis a solid changing into a gas. As a material sublimates, it does not pass through the liquid state. An example of sublimation is carbon dioxide, a gas, changing into dry ice, a solid. It is the reverse of deposition.

Depositionis a gas changing into a solid without going through the liquid phase. It is an uncommon phase change. An example is when it is extremely cold outside and the cold air comes in contact with a window. Ice will form on the window without going through the liquid state.

A pH of 7 is a neutral solution, which is how pure water is classified. Researchers can determine the strength of an acid or a base by measuring the pH of a solution. The pH value describes how acidic or basic a solution is. On pH scale, shown below, if the number is less than 7 the solution is acidic. A pH greater than 7 means the solution is basic. When the pH is exactly 7, the solution is neutral.

A person can be a universal blood donor or acceptor. A universal blood donor has type O blood, while a universal blood acceptor has type AB blood.

There are several different types or groups of blood, andthe major groups are A, B, AB, and O. Blood group is a way to classify blood according to inherited differences of red blood cellantigensfound on the surface of a red blood cell. The type ofantibodyin blood also identifies a particular blood group. Antibodies are proteins found in the plasma. They function as part of the body’s natural defense to recognize foreign substances and alert the immune system.

Depending on which antigen is inherited, parental offspring will have one of the four major blood groups. Collectively, the following major blood groups comprise the ABO system:

• Blood group A: Displays type A antigens on the surface of a red blood cell and contains B antibodies in the plasma.
• Blood group B: Displays type B antigens on the red blood cell’s surface and contains A antibodies in the plasma.
• Blood group O: Does not display A or B antigens on the surface of a red blood cell. Both A and B antibodies are in the plasma.
• Blood group AB: Displays type A and B antigens on the red blood cell’s surface, but neither A nor B antibodies are in the plasma

In addition to antigens, the Rh factor protein may exist on a red blood cell’s surface. Because this protein can be either present (+) or absent (-), it increases the number of major blood groups from four to eight: A+, A-, B+, B-, O+, O-, AB+, and AB-.