Answer the following question given this paragraph: When chemists synthesize a new compound, they may not yet know its molecular or structural formula. In such cases, they usually begin by determining itsempirical formula, the relative numbers of atoms of the elements in a compound, reduced to the smallest whole numbers. Because the empirical formula is based on experimental measurements of the numbers of atoms in a sample of the compound, it shows only the ratios of the numbers of the elements present. The difference betweenempirical and molecular formulas can be illustrated with butane, a covalent compound used as the fuel in disposable lighters. The molecular formula for butane is C4H10. The ratio of carbon atoms to hydrogen atoms in butane is 4:10, which can be reduced to 2:5. The empirical formula for butane is therefore C2H5. The formula unit is the absolutegrouping of atoms or ions represented by the empirical formula of a compound, either ionic or covalent. Butane, for example, has the empirical formula C2H5, but it contains two C2H5 formula units, giving a molecular formula of C4H10. Because ionic compounds do not contain discrete molecules, empirical formulas are used to indicate their compositions. All compounds, whether ionic or covalent, must be electrically neutral. Consequently, the positive and negative charges in a formula unit must exactly cancel each other. If the cation and the anion have charges of equal. Q: All compounds, whether ionic or covalent, must be what? Choices: - abnormal neutral - organic neutral - metallic neutral - electrically neutral A:
electrically neutral

Answer the following question given this paragraph: Stratus clouds occur low in the troposphere. They form in layers that spread horizontally and may cover the entire sky like a thick blanket. Stratus clouds that produce precipitation are called nimbostratus. The prefix nimbo- means "rain. ". Q: Where do stratus clouds occur in the troposphere? Choices: - mid to high region - high - mid-region - low A:
low

Answer the following question given this paragraph: A sex chromosome is a chromosome that determines the sex of an organism. Humans have two sex chromosomes, X and Y . Females have two X chromosomes ( XX ), and males have one X and one Y chromosome ( XY ). An autosome is any chromosome other than a sex chromosome. If a trait is autosomal it will affect males and females equally. Q: What chromosome determines the sex of an organism? Choices: - ribosome - S chromosome - autosome - sex chromosome A:
sex chromosome

Answer the following question given this paragraph: The type of radiation, which dictates how far it can penetrate into matter 2. The energy of the individual particles or photons 3. The number of particles or photons that strike a given area per unit time 4. The chemical nature of the substance exposed to the radiation The relative abilities of the various forms of ionizing radiation to penetrate biological tissues are illustrated inFigure 20.12 "Depth of Penetration of Ionizing Radiation". Because of its high charge and mass, radiation interacts strongly with matter. Consequently, it does not penetrate deeply into an object, and it can be stopped by a piece of paper, clothing, or skin. In contrast, rays, with no charge and essentially no mass, do not interact strongly with matter and penetrate deeply into most objects, including the human body. Several inches of lead or more than 12 inches of special concrete are needed to completely stop rays. Because particles are intermediate in mass and charge between particles and . Q: The type of what dictates how far it can penetrate into matter, such as lead or human flesh? Choices: - insulation - evaporation - specific gravity - radiation A:
radiation