The Chemical Basis of Life

Which of these are properties of water?

• Water is polar, each molecule has a slight positive/negative charge.

• Water is the universal solute.

• The hydrogen bonds allow water to stabilize temperatures well.

• Water has adhesive properties -- molecules stick to other water molecules.

• The hydrogen bonds make water an acid.

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Which of the following are true about atoms?

• Uncharged atoms have the same number of protons, electrons, and neutrons.

• Atoms of different elements bond together to create compounds.

• The atomic number is always equal to the number of electrons.

• The atomic mass is the combined number of protons and neutrons.

• Sometimes occur as isotopes with more/fewer neutrons.

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NGSS.MS-PS1-1

Salt...

• is formed from a polar covalent bond between sodium and chloride.

• contains iodine to help prevent goiters.

• is formed when chlorine donates a single electron to sodium.

• is an example of an ionic compound between a metal and nonmetal.

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NGSS.MS-PS1-1

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What are the most common elements in the human body?

• Carbon

• Nitrogen

• Water

• Oxygen

• Hydrogen

Which of the following are false statements about pH?

• A high pH is an indication of an acid.

• Acids have an increased number of hydrogen ions present.

• Is measured on a scale that progresses by a multiple of 100.

• A neutral pH has the same number of OH- ions and H+ ions.

Hydrogen...

• has one electron and one proton.

• bonds are responsible for holding nearby molecules together.

• atoms in water are slightly positively charged, which are attracted to the slightly negatively charged oxygens of other water molecules.

• concentration is measured on a scale called pH

• has one valence electron and requires another 7 electrons to fill its outermost orbital.

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NGSS.MS-PS1-1

Radioactive isotopes...

• have unstable nuclei

• dissipate excess energy at a predictable rate.

• change into different elements over time.

• serve no functional purpose.

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