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Marcus discovered that sodium (na) is found in group 1, period 3 on the periodic table. where should marcus look to find another element that has similar properties to those of sodium? a in group 1 b in period 3 c on the opposite side of the periodic table d at elements whose symbols begin with the letter n the diagram shows a test tube of pure copper (ii) sulfate, cuso4, solution before, during, and after the addition of iron, fe, shavings. image 9c3898c4b1ac4df0b1cbbb42fdbf2cbd which of the following correctly makes and supports a claim about the change that occurred? a a physical change occurred which is evidenced by the change in color of the solution. b a chemical change occurred which is evidenced by the change in color of the solution. c a physical change occurred which is evidenced by the dissolved iron in the solution. d a chemical change occurred which is evidenced by the dissolved iron in the solution. the table shows the procedure for an experiment. step procedure 1 crush 5 grams of salt into a fine powder. 2 transfer the powder to a beaker filled with 30 milliliters of liquid water. 3 place the beaker on a hot plate and stir to dissolve the powder. 4 boil water until all of the liquid water evaporates and the solid salt is left in the beaker. which best describes the change that occurred? a physical change because the atoms rearranged to form a new substance b chemical change because dissolving a solid into a liquid cannot be reversed c chemical change because the state of the salt changed from solid to liquid when dissolved d physical change because the chemical properties of the salt and water remained the same lewis has two spheres made of different substances. sphere a has a volume of 19.4 cubic centimeters and a mass of 24.0 grams. sphere b has a volume of 17.0 cubic centimeters and a mass of 13.6 grams. lewis knows that the density of water is 1.0 gram/cubic centimeter. if lewis places both spheres in a tub of water, which will float? a sphere a will float because it is less dense than sphere b. b sphere a will float because it has more mass than water. c sphere b will float because it has less mass than sphere a. d sphere b will float because it is less dense than water. the park groundskeeper rakes leaves in the fall. which of the following is a physical change he could apply to the leaves? a setting them on fire b allowing them to decay c shredding them into smaller pieces d putting them in acid to break them down eliana creates a model of an atom of the element sodium (na). she uses white pom-poms to represent electrons, black pom-poms to represent neutrons, and yellow pom-poms to represent protons. using the periodic table, which statement correctly describes her model? select all that apply. a her model uses eleven white pom-poms. b her model uses twelve black pom-poms. c her model uses eleven black pom-poms. d her model uses twelve white pom-poms. e her model uses eleven yellow pom-poms. f her model uses twenty-three yellow pom-poms. the diagram below shows what happens with two substances, a and b, are mixed together. image which of the following could explain why the two liquids formed distinct layers? a the liquids have different colors. b the liquids have different densities. c the liquids have different volumes. d the liquids have different states of matter. gracie hasn't ridden her bike in a few years and has now decided to sell it at her mom's garage sale. when she gets the bike out from under her deck, she makes the following observations about the bike. the bike is rusted. the seat cover has a smooth texture. the front basket of the bike is purple. which of the following choices describes the properties gracie observed? a physical properties: color, texture, ability to rust chemical properties: none b physical properties: none chemical properties: color, texture, ability to rust c physical properties: color, ability to rust chemical properties: texture d physical properties: color, texture chemical properties: ability to rust santi has two balloons. one balloon is filled with 1 liter of helium gas, and the other is filled with 1 liter of liquid water. santi places each balloon into separate, sealed 8 l containers. the pictures show the sealed containers and balloons. when both balloons burst, they release their contents into the sealed containers. after a few moments, what will be the volume of helium gas and liquid water in the containers? a container a will have 1 liter of helium, and container b will have 1 liter of water. b container a will have 1 liter of helium, and container b will have 8 liters of water. c container a will have 8 liters of helium, and container b will have 1 liter of water. d container a will have 8 liters of helium, and container b will have 8 liters of water.

1 Answer

+6 votes
by (100 points)
1. A. Group 12. B. A chemical change occurred which is evidenced by the change in color of the solution.3. D. Physical change because the chemical properties of the salt and water remained the same. 4. D. Sphere B will float because it is less dense than water.5. C. Shredding them into smaller pieces.6. A. Her model uses eleven white pom-poms.    B. Her model uses twelve black pom-poms.    E. Her model uses eleven yellow pom-poms.7.  B. The liquids have different densities.8.  D. Physical Properties: color, texture Chemical Properties: ability to rust9.  A. Container A will have 1 liter of helium, and container B will have 1 liter of water.Explanation:1. In the periodic table, rows represent the period that they are in, while columns represent the groups that elements are in. Elements in the same group (column) share similar properties. Since Sodium (Na) is found in group 1, elements that are similar in properties would be found in the same group. 2.  A chemical change is marked with a change in color, production of gas, heat, and sometimes smell and light. A chemical change results in new products formed, in which the properties and identities of the reactants change as well because their atoms were rearranged. In this case, the change in color of solution shows that a chemical change had occurred. 3. Earlier we said that chemical change results in new products, for physical change it does not. The substance will keep its identity. Like in the scenario, the salt and water did mix together, but when they were separated through evaporation, the salt retained its identity and so did the water. The substances involved merely changed phases. So this was a physical change. 4. If the density of the object is more than the density of the liquid, the object will sink. On the other hand, if the density of the object is less than the density of the liquid, it will float. If water has a density of 1g/cm³, the object that has the lesser density will float. First you solve for the densities of each object and it can be computed using the formula:D = m/vwhere D = density; m = mass; and v = volumeSphere A:Sphere B:So as you can see, only Sphere B has a density less or is less dense than water, so only Sphere B will float.  5. The groundskeeper shredding leaves is an application of physical change. As you can see, the identity of the leaves would be the same if you just shred them. Even if they change in shape and size, the leaves are still leaves, only smaller. 6. A stable atom has the same number of electrons and protons. The number of protons is represented by the atomic number of an element.Sodium has an atomic number of 11. This means that there are 11 protons (yellow pom poms) in a sodium atom. Since it is stable, you can also say that there are 11 electrons (White pom poms) as well.  The number of neutrons can be determined by taking a look at the mass number of an atom. The mass number of sodium is 23. The mass number is the number of protons and neutrons combined. 23 = p + n23 = 11 + n23 - 11 = n12 = nThe number of neutrons would be 12 (black pom poms). 7. When two liquids do not mix, this means they are immiscible. The layers are formed because of the difference in density. Remember earlier about density and an object or substance's ability to float? Well it applies here too. The liquid on top is less dense than the one below it, so it floats up and the denser liquid sinks. 8. Physical properties are things that you can observe using your senses. Chemical properties are properties that you can only observe when chemical structure is changed. Seat cover has a smooth texture.   Physical because it was determined by touch. The front basket of the bike is purple. Physical because it was determined by sight.The bike is rusted. Chemical because the metal changed its chemical structure as a result of a reaction. 9. The sealed containers represent a closed system, or a vacuum where nothing goes in or out. In a closed system, just remember that matter is not created, nor destroyed. Simply put, this means that whatever it started with is what will it end up with. In container A you have 1 L of helium gas, so since the container is sealed, none escaped. This means that you will end up with the same amount of helium gas as you did before. The same goes for the 1L of water in container B.  

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