8th Grade week 12 CCA 2013

1. two liquids of the same temperature are mixed in an open beaker to produce one liquid that has escaping gas bubbles. The gas produced is evidence of what event?

A. Phase Change

B. Solution formation

C. Chemical reaction

D. Mixture separation

3. When water combines with fertilizer (ammonium nitrate), an endothermic reaction occurs. How can this type of reaction be used?

a.to heat food c.to produce sound

b.to create light d.as a cold pack

4. Na and Cl bond together because of valence electrons. What other elements would also bond with Na, due to similar properties, and form a similar solid substance?

A.K, MGB.Ar, LiC.F, BrD.Cu, Ne

5. In a car engine, the reaction between gasoline and oxygen is exothermic because:

a. the reaction absorbs energy in the form of heat

b. it cools the engine parts to reduce friction

c. the reaction releases energy in the form of heat

d. it is a chemical reaction that makes the car move fast

6. When this reaction is observed, gas bubbles are visible rising to the surface of the liquid hydrogen peroxide and the color of the solution remains clear. The graph shows what happens to the temperature of the liquid as it is monitored over time.What are the sign(s) that a chemical change has occurred?

A. The formation of gas bubbles and the rise in temperatureB. Only the formation of gas bubblesC. A precipitate formedD. A color change was observed

7. When carbon and oxygen combine chemically, the mass of the product is :

A. greater than the mass of the carbon plus the mass of the oxygen

B. equal to the mass of the carbon plus the mass of the oxygen

C. equal to the mass of the carbonD. less than the mass of the carbon

8. How many neutrons does the atom in the model shown below have?

A. 9

B. 10

C. 16

D. 2

9. Joshua placed 4 grams of baking soda in a balloon and 200mL of vinegar in an Erlenmeyer flask. After stretching the opening of the balloon across the neck of the flask, the student raised it to dump the baking soda into the flask. He immediately observed foaming bubbles in the flask and the balloon began to expand, Joshua concluded that

A. the bubbles indicated a chemical change was occurringB. the gas was hydrogenC. the baking soda and vinegar were products of a chemical reactionD. a physical change only was occurring

10. The picture above shows a blue liquid being carefully added from one test tube to a clear liquid in a second test tube for easiest observation. Which is the BEST evidence that a chemical reaction may have occurred?

A.The solution turned light blueB. The temperature remained the sameC. A precipitate (solid) was formedD. The volume increased

11. Which of the following is an example of a physical change?

A. Mixing baking soda and vinegar together, and this causes bubbles andfoam.B. A glass cup falls from the counter and shatters on the ground.C. Lighting a piece of paper on fire and the paper burns up and leaves ashes.D. Baking a birthday cake for your mother.

12. Which of the following is an example of chemical change?

A.Filling up a balloon with hot air.B.Taking a glass of water and freezing it by placing it in the freezer.C.A plant collecting sunlight and turning it into food.D. Your dog ripping up your homework.

13. The melting of wax is a physical change, yet the burning of the wick is a chemical change. What is the essential difference between the physical change and the chemical change of the wick in a burning candle?

A. The burning of wax forms new compounds, while the melting of wax does not.B. a higher temperature is needed to burn the wick then to melt wax. C. melted wax can be separated into other substances, while solid wax cannot.D. melted wax is a different phase of matter than solid wax.

14. When the fuse ignites the contentsof a firework, oxygen is consumed as

a result of what type of reaction?

A. Mass C. ChemicalB. Phase D. Nuclear

15. Which example indicates that a chemical change has occurred?

A. When two aqueous (liquid) solutions are mixed, a precipitate is formed.B. As ammonium nitrate dissolves in water, it causes the temperature of the water todecrease.C. Alcohol evaporates when left in an open container.D. Water is added to blue copper(II) chloride solution. The resulting mixture is lighter blue in color.

16. The element Argon (Ar) is an odorless, colorless Noble gas at room temperature. These elements do not react with other elements under normal circumstances. Which of these elements have these same physical properties?

Element Group PeriodW 17 3X 18 4Y 14 2Z 2 3

A.Element WB.Element XC.Element YD.Element Z

17. The element in the picture below is considered very stable and does not readily form compounds because

A. Its outer energy levels are empty and contain no electronsB. It is a solidC. It is a nonmetalD. Its outer energy level is completely filled with electrons

18.

19. One of the chemical reactions that occurs in the formation of glass is the combining of calcium carbonate (CaCO3) and silica (SiO2) to form calcium silicate (CaSiO3)and carbon dioxide (CO2), the formula below represents the reaction.

CaCO3(solid) + SiO2 --> CaSiO3 + CO2(gas)

Which of the following pieces of evidence gives proof of the chemical reaction?

A.The products are different from the reactantsB.The number of atoms of oxygen are differentC.The carbon changes from a solid to a gasD.The molecules of SiO2 are destroyed

20. You need to find the mass of an atom. This neutral atom has 7 negative particles and 8 neutral

particles. What is the mass of the atom and what is the name of the element that is being described?

A.7, LithiumB.7, NitrogenC.14, LithiumD.15, Nitrogen

21. The diagram below shows the formation of two water molecules

How many atoms combined to form the two molecules?

Bubble your answer into the correct placement value on the answer document.