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Which of the following is an example of a chemical change?

A. Releasing compressed gas to make a bottle-rocket launch

B. Adding water to clay to make slip

C. Crystalizing honey to make candy

D. Including baking soda in a recipe to make it less sour

Answer Explanation:

A chemical change involves a chemical reaction and new substances are produced. When baking soda is added to something sour (acidic) it neutralizes the acid and forms new molecules, in this case carbon dioxide and water. A physical change does not produce new substances. Phase changes such as evaporation and sublimation are physical changes. Changing the ratio of ingredients in a mixture, like adding more water to clay, does not change it chemically, but it can change some of the mixture's physical properties.

Therefore, the Correct Answer is D.

Q #1: Where is the gastrocnemius vein in relation to the femoral vein?

A. Lateral

B. Distal

C. Superior

D. Ventral

Answer Explanation

The gastrocnemius vein is found in the calf. The femoral vein is found in the proximal anterior thighs/pelvis.

Since the gastrocnemius vein is found below the femoral vein it is distal or inferior to the femoral vessel.
Q #2: Which of the following orbitals is the last to fill?

A. 1s

B. 3s

C. 4p

D. 6s

Answer Explanation

Of these orbitals, the last to fill is 6s.

Orbitals fill in the following order: 1s, 25, 2p. 35, 3p, 4s, 3d, 4p, 55, 4d, 5p. 6s, 4f, 5d, 6p. 7s, 5f, 6d, and 7p. The number is the orbital number, and the letter is the sublevel identification. Sublevels has one orbital and can hold a maximum of two electrons. Sublevel p has three orbitals and can hold a maximum of six electrons. Sublevel d has five orbitals and can hold a maximum of 10 electrons, Sublevel f has seven orbitals and can hold a maximum of 14 electrons.
Q #3: Your class is competing with another class to determine who has the best plant color. Your class decides to test a couple of solutions to determine which would be best for overall plant color before competing. Starting with four sets of four plants, the class decides to water each set with a different solution. They water them once a week with 200ml of the following solutions: water, diet soda, 1% bleach solution, and a 1% salt solution. All plants are placed in the window that receives the recommended amount of light. After a month of testing, your class notices that only two plants are alive, but one of those two does not look healthy. Based on these results, which of the following would be a good hypothesis to design the next experiment around?

A. Plants need more than 200 mL of liquid per week.

B. Salt has no impact on plant health.

C. Salt contains useful nutrients for plants.

D. A combination of the solutions tested will produce healthier plants.

Answer Explanation

Since only 2 out of the initial 16 plants survived the whole month, it would be reasonable to test variables that were shared by all the plants. As such, the amount of liquid the plants need would be a good follow-up experiment. It is not specified as to which plants survived, so there is not enough information to think that testing the impact of salt is warranted. Additionally, since almost all the plants died, it is not reasonable to assume that a combination of the solutions would have an impact.

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