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In a phase diagram, which of the following is the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously?    

A. Triple point

B. Critical temperature

C. Critical point

D. Absolute zero

Answer Explanation:

Triple point.

In a phase diagram, the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously is the triple point.

The triple point is a unique point on a phase diagram where the three states of matter (solid, liquid, and gas) can coexist in equilibrium.

At the triple point, the temperature and pressure of the substance are fixed.

Option B, critical temperature, is the temperature at which a gas cannot be liquefied, regardless of the pressure applied.

It is a characteristic property of a substance and is typically higher than the boiling point of the liquid at standard pressure.

Option C, critical point, is the point on a phase diagram where the liquid and gas phases of a substance become indistinguishable.

At the critical point, the distinction between the liquid and gas phases disappears, and the substance becomes a supercritical fluid.

Option D, absolute zero, is the theoretical temperature at which all matter has zero thermal energy.

At absolute zero, all substances are in their solid state, but it is not relevant to a phase diagram, as it is a temperature where no transitions between states occur.

In summary, the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously in a phase diagram is the triple point, whereas the other options provided are not relevant or are characteristic properties of substances in different contexts.

Therefore, the Correct Answer is A.

More Questions on TEAS 7 Science

  • Q #1: A myocardial infarction affects which of the following blood vessels of the heart?  

    A. Coronary

    B. Aorta

    C. Pulmonary

    D. Vena cava

    Answer Explanation

    A myocardial infarction affects the coronary blood vessels of the heart.

    A myocardial infarction, commonly known as a heart attack, occurs when blood flow decreases or stops in the coronary artery of the heart, causing damage to the heart muscle 1.

     

    Choice B is incorrect because the aorta is not a blood vessel of the heart.

    The aorta is the main artery that carries oxygenated blood from the heart to the rest of the body.

    Choice C is incorrect because the pulmonary blood vessels are not affected by a myocardial infarction.

    The pulmonary blood vessels carry deoxygenated blood from the heart to the lungs.

    Choice D is incorrect because the vena cava is not a blood vessel of the heart.

    The vena cava is a large vein that carries deoxygenated blood from the body to the heart.

  • Q #2: Which of the following statements best supports the hypothesis that viruses can cause cancer?

    A. Cancerous and normal cells share genetic sequences

    B. Cellular DNA has sequences related to viral sequences

    C. Viruses and cancer cells both replicate rapidly.

    D. Genes that regulate cell division are found in some viruses

    Answer Explanation

    Genes that regulate cell division are found in some viruses.

    When viruses cause an infection, they spread their DNA, affecting healthy cells’ genetic makeup and potentially causing them to turn into cancer.

    For instance, HPV infections cause the virus’ DNA to combine with the host’s DNA, disrupting the normal function of cells.

    Choice A is not correct because cancerous and normal cells sharing genetic sequences does not support the hypothesis that viruses can cause cancer.

    Choice B is not correct because cellular DNA having sequences related to viral sequences does not support the hypothesis that viruses can cause cancer.

    Choice C is not correct because viruses and cancer cells both replicating rapidly does not support the hypothesis that viruses can cause cancer.

  • Q #3: Which of the following substances protects the skin from ultraviolet radiation?  

    A. Melanin

    B. Perspiration

    C. Sebum

    D. Keratin

    Answer Explanation

    Melanin.

    Melanin is a pigment produced by cells called melanocytes in the skin.

    It protects the skin from ultraviolet (UV) radiation by absorbing and dissipating over 99.9% of absorbed UV radiation.

    This helps to prevent DNA damage and other adverse effects of UV radiation on the skin.

     

    Choice B.

    Perspiration is not correct because it is a fluid produced by sweat glands in the skin that helps to regulate body temperature, but it does not protect the skin from UV radiation.

    Choice C.

    Sebum is not correct because it is an oily substance produced by sebaceous glands in the skin that helps to lubricate and protect the skin, but it does not protect the skin from UV radiation.

    Choice D.

    Keratin is not correct because it is a fibrous protein that provides strength and durability to the skin, hair and nails, but it does not protect the skin from UV radiation.