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Maria and Carla were hiking when Maria tripped, fell, and sprained her ankle. Carla took out the first-aid kit and unwrapped a cold pack. Carla popped a vial that was inside the cold pack. The pack began to get icy cold and Carla applied the pack to Maria's ankle.What kind of reaction occurred in the cold pack? What evidence supports your answer?
A)It is a physical change as evidenced by a drop in temperature.
B)It is a chemical change because two different chemicals are mixed together.
C)It is a chemical change because heat energy is absorbed and the pack gets colder.
D)It is a physical change because the substance in the vial dissolved in the pack's liquid.
Your teacher burns a piece of steel wool in class, demonstrating the chemical property, flammability. You are curious to see what other things can demonstrate chemical properties. Which of these does NOT demonstrate a chemical change?
A)Burning sugar demonstrates a chemical change.
B)The rusting of steel wool demonstrates a chemical change.
C)Making soap by allowing fat to react with sodium hydroxide demonstrates a chemical change.
D)Measuring the freezing point of different concentrations of salt water demonstrates a chemical change.
A scoop of baking soda is added to a beaker containing vinegar. The baking soda disappears and bubbles are observed. This is an example of a _____________ change.
A)chemical
B)ionic
C)phase
D)physical
Students can use _________ to distinguish pure substances, such as elements and compounds with a constant composition, from other substances.
A)color
B)density
C)particle size
D)state of matter
Justin Bleeber is a lazy young man and decides to burn a pile of leaves instead of bagging it. The pile of leaves weighed three pounds before being burned. After the leaves are burned the leftover ash weighs half a pound.What happened to the rest of the mass of the leaves?
A)It was destroyed.
B)It soaked into the ground.
C)It compacted into the ash.
D)It was turned into smoke and gas.
Which of these is common to all chemical changes?
A)A change of state occurs.
B)A change of color occurs.
C)A new substance is produced.
D)Heat is released into the air.
Steel wool is often used to clean up pans. Steel wool is mostly iron (Fe). In fact, steel is an iron alloy: iron with about 2% carbon. In lab, you burn steel wool, creating quite a spectacular glowing mass. What kind of property is being demonstrated, and how do you know?
A)Burning steel wool demonstrates a chemical property, flammability.
B)Burning steel wool demonstrates the physical property because heat is being produced.
C)Burning steel wool demonstrates a physical property because a color change is being observed.
D)Burning steel wool demonstrates a chemical property, observing the melting point of the iron.
Which image displays a chemical property about a substance? Choose all that apply.
A)II and IV
B)I, IV, and V
C)I, III, and V
D)II, III, and IV
When mixing 2 or more substances together, evidence that a chemical change occured would NOT include
A)producing a gas.
B)change in color.
C)change in shape.
D)change in temperature.
Your teacher wants you to perform an experiment that will demonstrate a chemical property. Which experiment should you choose?
A)Measure the pH of different household chemicals
B)Form a density column using common household materials.
C)Measure the melting point of common household chemicals.
D)Measure the solubility of different household substances.
Which of these is common to all chemical changes?
A)A change of state occurs.
B)A change of color occurs.
C)A new substance is produced.
D)Heat is released into the air.
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