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What solution has a pH of 7?

A. Aniline

B. Pyridine

C. Pure water

D. Sodium hydroxide

Answer Explanation:

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.

Therefore, the Correct Answer is C.

More Questions on TEAS 7 Science

  • Q #1: Which blood group is a universal donor?

    A. A

    B. B

    C. AB

    D. O

    Answer Explanation

    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, and the major groups are A, B, AB, and O. Blood group is a way to classify blood according to inherited differences of red blood cell antigens found on the surface of a red blood cell. The type of antibody in 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-.

     

  • Q #2: Blood oxygen levels are most likely low when blood _____.

    A. leaves the aorta

    B. fills the right atrium

    C. reaches body tissues

    D. flows through arteries

    Answer Explanation

    Blood continually flows in one direction, beginning in the heart and proceeding to the arteries, arterioles, and capillaries. When blood reaches the capillaries, exchanges occur between blood and tissues. After this exchange happens, blood is collected into venules, which feed into veins and eventually flow back to the heart’s atrium. The heart must relax between two heartbeats for blood circulation to begin.

    Two types of circulatory processes occur in the body:

    Systemic circulation

    • The pulmonary vein pushes oxygenated blood into the left atrium.
    • As the atrium relaxes, oxygenated blood drains into the left ventricle through the mitral valve. 3. The left ventricle pumps oxygenated blood to the aorta.
    • Blood travels through the arteries and arterioles before reaching the capillaries that surround the tissues.

    Pulmonary circulation

    • Two major veins, the Superior Vena Cava and the Inferior Vena Cava, brings deoxygenated blood from the upper and lower half of the body.
    • Deoxygenated blood is pooled into the right atrium and then sent into the right ventricle through the tricuspid valve, which prevents blood from flowing backward.
    • The right ventricle contracts, causing the blood to be pushed through the pulmonary valve into the pulmonary artery.
    • Deoxygenated blood becomes oxygenated in the lungs.
    • Oxygenated blood returns from the lungs to the left atrium through the pulmonary veins.

  • Q #3: Which part of the digestive system comes before the stomach?

    A. mouth

    B. esophagus

    C. ileum

    D. colon

    Answer Explanation

    Oral Cavity is the first part of the digestive system. It is bounded by the lips and cheeks and contains the teeth and tongue. Its primary function is to masticate, or chew, and moisten the food.

    Pharynx, or throat, connects the mouth to the esophagus.

    Esophagus is a muscular tube about 25 centimeters long. Food travels down it to the cardiac sphincter of the stomach.

    Pyloric sphincter. The exit of the stomach.

    Small intestine is about 6 meters long and consists of three parts: duodenum, jejunum, and ileum.

    Large intestine, consists of the cecum, colon, rectum, and anal canal. The cecum is located where the small and large intestine meet. The primary function of the large intestine is to compress the waste and collect any excess water that can be recycled.

    Colon is about 1.5 to 1.8 meters long and consists of four parts: the ascending, transverse, descending, and sigmoid colon.