Dallas ISD Science Department Based on their location on the periodic table, which of the following pairs of atoms would most likely share electrons when bonding? A. Al and F B. Ca and I C. Na and Cl D. P and O
Dallas ISD Science Department An unidentified element has many of the same physical and chemical properties as magnesium and strontium but has a lower atomic mass than either of these elements. What is the most likely identity of this element? F Sodium G Beryllium H Calcium J Rubidium
Dallas ISD Science Department Although it is located in Group 1A and can form ions, hydrogen most frequently shares electrons to become stable. What type of bond is shown in the figure above and why? A.ionic, because hydrogen loses the electron gained by chlorine B.polar covalent, because there is unequal sharing of electrons C.pure covalent, because any sharing of electrons is covalent D.pure covalent, because there is equal sharing of electrons
Dallas ISD Science Department B. polar covalent, because there is unequal sharing of electrons
Dallas ISD Science Department Compared to 250 g of gaseous nitrogen, 250 g of liquid nitrogen has greater — A volume B temperature C mass D density
Dallas ISD Science Department Swimmers find that they can float more easily in the ocean than in a freshwater pond. The most likely reason for this phenomenon is that the — A viscosity of pond water is greater than that of ocean water B density of ocean water is higher than that of pond water C temperature of pond water is lower than that of ocean water D mass of ocean water is greater than that of pond water
Dallas ISD Science Department B density of ocean water is higher than that of pond water
Dallas ISD Science Department This pipette is filled with a 20% NaOH solution. The solution is at 20°C and has a density of 1.23 g/mL. According to this information, what is the mass of this NaOH solution? A 3.88 g B 15.7 g C 23.9 g D 24.6 g
Dallas ISD Science Department Which of the following statements is true regarding the relationship between temperature and solubility in water? A. All solids become more soluble as temperature increases. B. An increase in temperature of the water usually results in more solid solute dissolving. C. Gases become more soluble as temperature increases. D. The effect of temperature on the solubility of both gases and solids is the same.
Dallas ISD Science Department B. An increase in temperature of the water usually results in more solid solute dissolving.
Dallas ISD Science Department Suppose you need water that contains more oxygen than usual. You plan on bubbling air, which contains oxygen, into the water. What would you do to increase the amount of oxygen that will dissolve in the water? A.Decrease the pressure on the system. B.Decrease the temperature of the water. C.Make water molecules more polar. D.Stir the water.
Dallas ISD Science Department A. Decrease the temperature of the water.
Dallas ISD Science Department Which of these changes in rocks is a physical change? A Acid rain damaging marble B Iron in rock combining with oxygen to form hematite C Carbonic acid weathering limestone D An ice wedge shattering a slab of shale
Dallas ISD Science Department D An ice wedge shattering a slab of shale
Dallas ISD Science Department When the above equation is balanced, the coefficient for magnesium chloride is — A 0 B 1 C 2 D 4
Dallas ISD Science Department If all the reactants in a chemical reaction are completely used, which of the following statements accurately describes the relationship between the reactants and the products? F The products must have a different physical state than the reactants. G The total mass of the reactants must equal the total mass of the products. H The reactants must contain more complex molecules than the products do. J The density of the reactants must equal the density of the products.
Dallas ISD Science Department G The total mass of the reactants must equal the total mass of the products.
Dallas ISD Science Department What type of change is shown in the diagram above, which shows a distillation setup? A.a physical change B.a chemical change C.both a chemical change and a physical change D.neither a chemical nor a physical change
Dallas ISD Science Department A. a physical change
Dallas ISD Science Department Which chemical equation supports the law of conservation of mass? F 2H2O(l) → H2(g) O2(g) G Zn(s) HCl(aq) → ZnCl2(aq) H2(g) H Al2C3(s) H2O(l) → CH4(g) Al(OH)3(s) J CH4(g) 2O2(g) → CO2(g) 2H2O(g)
Dallas ISD Science Department J CH 4 (g) 2O 2 (g) → CO 2 (g) 2H 2 O(g)
Dallas ISD Science Department Over time an open soft drink will lose carbonation (dissolved CO 2 ). Which of these allows the CO 2 to remain in solution the longest? A Reduced air pressure B Exposure to direct sunlight C Increased air currents D Cooler temperatures
Dallas ISD Science Department D Cooler temperatures
Dallas ISD Science Department In this apparatus, the seawater is an example of a — F strong electrolyte G weak acid H nonelectrolyte J strong base
Dallas ISD Science Department F strong electrolyte
Dallas ISD Science Department Which of the following statements is true regarding the effect of thermal pollution on the organisms living in a lake? A.More dissolved oxygen will be present because an increase in temperature will increase the solubility of oxygen in the water. B. The lake will be able to support more organisms because organisms grow better in warm water. C. The water in the warmer lake will contain less dissolved oxygen, so fewer organisms that require oxygen will be able to live there. D. Thermal pollution has no effect on the organisms involved.
Dallas ISD Science Department C. The water in the warmer lake will contain less dissolved oxygen, so fewer organisms that require oxygen will be able to live there.
Dallas ISD Science Department Fish survive through severe winters because of the property of water that allows water to — F form chemical bonds as it freezes, raising the water temperature below the ice G increase in density while it freezes, dissolving more oxygen from the air H expand when it freezes, creating a floating and insulating layer of ice J precipitate vital nutrients when it freezes, increasing the food supply
Dallas ISD Science Department H expand when it freezes, creating a floating and insulating layer of ice
Dallas ISD Science Department Oil is nonpolar, water is polar, and the two do not dissolve in each other. The figure shows how soap cleans oily dirt. From the diagram, which of the following statements best summarizes how soap enables water to remove oil? A. Soaps contain alcohol, which dissolves oils. B. The charged part of soap makes oil polar, and it dissolves in water. C. The nonpolar part of soap dissolves in oil, and its charged part is attracted to water. D. The nonpolar tail of a soap molecule knocks loose the oil particles.
Dallas ISD Science Department C. The nonpolar part of soap dissolves in oil, and its charged part is attracted to water.